More and more apps and websites are offering cash back when you shop. But, those offers come with some strings attached

I always tell you if you have to shop, get rewards for it either with a credit card or rewards program.

Here’s a look at a few apps and websites offering cash back. USA Today researched, although catch it, most require you to link a credit card to get the perks.

One of them is Groupon. That deal site is offering cash back for purchases at chains like Dunkin’ Donuts, Panda Express and Starbucks. You link a card then claim a deal for a specific store.

And check out the offers from Ebates and RetailMeNot. Both offer cash back on purchases from Amazon, Sephora and other big name retailers.

The cash back for that one is good for both online and in-store purchases.

Also worth a look is the app “Drop.” It lets you earn points which you can then turn into store gift cards. That’s another one you’ll need to link a credit or debit card.

Then the points are earned automatically when they card is used at a variety of merchants including Macy’s and McDonald’s.

Just a few ways to save a couple bucks at stores you’re likely shopping at anyway.