law of adulting: veg spoils 5x faster when ur paying for it

Soak a kitchen towel, wring it out, and line the bottom of the crisper with it. Feel it every once in a while to make sure it's still damp. That'll let your crisper be what it was designed to be: a little high-humidity box in an otherwise arid refrigerator.

Also, take note of how produce is stored at the grocery store. If the store doesn't refrigerate something (apples, tomatoes, avocados to name a couple), odds are you shouldn't either. The fruits and veggies that belong in the crisper are the ones that are periodically misted with water in the case at the store. Also probably don't keep anything tightly wrapped in plastic.