The limitations varied. With beauty products, I had $10 towards any sort of beauty products. With pet food, I had $15 towards anything from the companies in the box.
But I really found the sample boxes worth it.
Make your own sample box
Now, Amazon is letting you build your own sample box. You pay for each sample individually, but then you get 100% credit towards products in the future.
They end up being more expensive per sample, but you get to choose exactly what you want. In addition, you’ll get the cost back in credit if you end up purchasing full-size products.
When redeeming your credit
Some people have reported having trouble redeeming the credit. When I first purchased items, I screenshotted what it said I can redeem the credit for–just in case. The text on the pages never changed, so I never actually needed that as proof.
Sometimes, I couldn’t get the credit to apply to some items in my order that were clearly included in the rules for the credit. Each time, I logged onto chat and they fixed it for me. In a couple of cases, they applied a separate credit as an apology for the trouble (and I ended up having the original credit applied to a future order!)
YMMV, but I’ve had all my problems resolved reasonably well by the online chat.
Please note, if you buy anything through my Amazon links, I may receive referral credit. As always, I appreciate your support!