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Flex Upsell Cart: Shopify Cart Upsell App
Flex Upsell Cart turns your cart into the place where order value goes up: a free shipping and free gift bar, 1-click upsells, shipping protection and buy more save more offers, in a cart designed to match your store. We built it for our own client stores, and it runs on stores like Glittered Crafts, More Than Lips and Envida Jewelry.
- 5.0 on the Shopify App Store
- Built for Shopify
- Free plan, $19/month for 7 offers
- 135+ Shopify stores
What a Shopify cart upsell app does
The cart is the one moment every buyer sees, and they already decided to buy. A plain theme cart shows the items and a checkout button. Flex Upsell Cart adds the offers that make people add one more thing:
- Free shipping and free gift progress bar. "You're $12 away from free shipping" with tiers for a gift or a discount on bigger orders.
- 1-click upsells and cross-sells. Products picked by AI from what's in the cart, or the ones you choose, added with one tap.
- Add-ons in a checkbox. Shipping protection, gift wrap or priority processing, on or off with one click.
- Buy more, save more. For example 10% off at $150 and 15% off at $250.
- Subscription upgrade. Switch a one-time item to subscribe and save right in the cart.
- Your brand, any language. Full design control with CSS, AI translation and the right currency for each country.
- Cart analytics. How many people saw each offer, took it and how much revenue it added.
Results from client stores
We install Flex Upsell Cart on the stores we build and manage, then check the numbers after the first week.
Shipping protection: $22,494 from one checkbox
A US store with a lot of small orders. We added shipping protection to the cart for $4.95, using the Checkbox upsell with Checkout+ mode on: the checkout button shows the new total with protection, and a small "Checkout without protection" link sits right under it.
- $22,494 extra revenue from 5,082 orders in 202 days
- 79% of shoppers kept the protection on
- $12,378 of it in the last 90 days alone
Read the full shipping protection case study, with the setup steps and the mistakes to avoid.
A fragrance store: 1,100+ orders with offers
A fragrance oil store we work with every month. The cart shows recently viewed oils that shoppers add in one tap, and the offers run without getting in the way of checkout.
Shoppers add a second oil from the cart without going back to the store.
More results from stores using the app
Results from stores using Flex Upsell Cart, as shown on flexupsell.com. Store names hidden.
The cart is also part of our full store builds, like the dotdotsee custom Shopify store.
Which cart offer to use for your store
More offers is not better. One or two offers that fit your products work best, and you add more once you see the numbers. This is where we start on most stores:
| Offer | What it does | Best for |
|---|---|---|
| Free shipping bar | Shows how much more to spend for free shipping | Almost every store. Set the goal about 20 to 30% above your average order |
| Free gift tier | Unlocks a gift at a higher cart value | Beauty, fragrance and gift stores with a cheap but nice extra product |
| Shipping protection | Adds $3.95 to $4.95 to cover lost or damaged packages | Stores with many small orders and a lot of shipping questions |
| 1-click upsell | Suggests a matching product to add in one tap | Refills, accessories, a second size or color |
| Buy more, save more | A bigger discount at bigger cart values | Products people buy several of, like oils, supplements or snacks |
| Subscription upgrade | Switches a one-time item to subscribe and save | Products people reorder. See our subscription product page setup |
Flex Upsell Cart vs UpCart vs Kaching Cart
These are the cart apps we're asked about most. All three give you a cart drawer with a progress bar and upsells. The difference is how the price grows with your orders, and how much help you get with the design.
| Flex Upsell Cart | UpCart | Kaching Cart | |
|---|---|---|---|
| Free plan | Yes, on live stores, with 1 offer | Only for development stores | Only for development stores |
| Paid plans | $19/month for up to 7 offers | $29.99 to $54.99/month by orders | $9.99 to $24.99/month by orders |
| At 1,000 orders a month | $19 | $54.99 | $24.99 |
| Free trial | 14 days | 14 days | 14 days |
| Shopify App Store rating | 5.0 (18 reviews) | 4.8 (956 reviews) | 5.0 (1,617 reviews) |
| Built for Shopify | Yes | Not shown | Yes |
| Design help | Our team designs the cart in your brand | Templates and settings | Templates and settings |
Prices and ratings from the Shopify App Store, November 2026. Kaching's $24.99 is its highest listed plan.
UpCart and Kaching have many more reviews, and both are good apps. We recommend Flex Upsell Cart when you want one flat price as your orders grow and a cart designed by people who build Shopify stores every day. If you already use another cart app and it works, keep it, and use the offer table above to get more from it.
How we set up Flex Upsell Cart on your store
You can install the app and turn on a progress bar yourself in about 10 minutes. When our team sets it up, this is the order we work in:
- Look at your numbers. Average order value, best sellers and which products are bought together, from your Shopify reports.
- Design the cart in your brand. Colors, fonts, buttons and badges that match your theme, on desktop and phone.
- Pick 1 or 2 offers. Usually the free shipping bar plus the offer from the table above that fits your products.
- Test before launch. Discounts, free shipping, subscriptions and the checkout button, in every currency you sell in.
- Check after 7 days. We look at how many people took each offer in the cart analytics, then add or change one offer at a time.
Want the whole cart and checkout looked at, not only the app? See our Shopify cart and checkout optimization or get a free store analysis.
Flex Upsell Cart pricing
Plans billed through Shopify, from the Shopify App Store listing, November 2026.
What store owners say
"Easy setup, higher conversions"
Envida JewelryCanada. Shopify App Store review
"One of the smartest apps we have"
Glittered CraftsShopify App Store review
"Great app, great support"
That Bunny FarmShopify App Store review
"Flex Upsell Cart has been a great investment"
Prado ActivewearUnited States. Shopify App Store review, May 2026
Questions about Shopify cart upsell apps
What is the best cart upsell app for Shopify?
The one that fits your store and that you actually set up well. Flex Upsell Cart, UpCart and Kaching Cart all do the basics: a cart drawer, a progress bar and upsells. Flex Upsell Cart has a free plan on live stores and one flat $19 price as your orders grow, and our team can design it for you. Kaching and UpCart have more reviews and price their plans by orders.
Is Flex Upsell Cart free?
Yes. The free plan includes the free shipping bar, 1 offer, 1-click upsells, add-ons like shipping protection and gift wrap, full design control and AI translation. The AOV Boost plan is $19 a month for up to 7 offers and priority support, with a 14-day free trial.
Does it work with my Shopify theme?
It works with any Shopify theme. It replaces your theme's cart drawer with its own, styled to match your store. If you have a custom theme, our team helps with the setup.
Will a cart app slow down my store?
Any app adds some code. Flex Upsell Cart replaces your cart instead of stacking a second cart on top of the theme's, which keeps it lighter. Run Google PageSpeed before and after you install any cart app, so you see the real difference on your store.
How do I add shipping protection to my Shopify cart?
Create a Shipping Protection product, hide it from your store and search, then turn on the Checkbox upsell in Flex Upsell Cart and pick that product. Turn on Checkout+ mode so the protection shows on the checkout button, with a link to check out without it. Our shipping protection case study has every step.
What free shipping threshold should I set?
A good start is about 20 to 30% above your average order value. Most shoppers are then close enough to add one more item. Check your average order value in Shopify Analytics first, and change the goal after a few weeks of data.
Can I show offers in other languages and currencies?
Yes. Flex Upsell Cart translates the cart with AI and shows prices in the shopper's currency, so stores selling to several countries keep one cart.
Can you design and set it up for me?
Yes. Our team designs the cart in your brand, sets up the offers that fit your products and checks the numbers after the first week. Send us your store link for a quote.
Nick Ursu, 8+ years Shopify Conversion Expert
I've worked on Shopify stores since 2017, with 1,300+ projects since then. My team and I built Flex Upsell Cart for our own client stores, and we design carts, product pages and checkouts that sell.
Last updated November 2026. App prices and ratings from the Shopify App Store, results from our client projects and flexupsell.com.
Want more from every order?
Install Flex Upsell Cart for free, or send me your store link and I'll tell you which cart offer I'd start with.