Wet/Dry Bags -- They might not seem like the most glamorous purchase, but you will use these bags for so many uses during your child's life. It's a wet bag with an additional zipper for dry items you might need to tuck away. So while you're out and about, you can put soiled clothes/cloth diapers in the wet bag zipper, and a clean change of backup clothes in the dry bag zipper.
Wet/dry bags are traditionally made for cloth diapering, but you don't have to be an exclusively cloth diapering to utilize and love these wet/dry bags. Here are some other uses where they come in handy!
Potty Learning
Wet Swimming Suits after a trip to the pool or beach
Tossing your sweaty clothes in after the gym
A catch-all bag for your car
A Stroller bag
Transporting breast pump supplies after you've used them
Traveling -- Keep anything in your wetbag that you don't want to get damaged by water (Passports, electronics), or to keep dirty things from damaging other items in our suitcase (like sneakers or sandals)
You can find a variety of brands, sizes, and prints for Wet/Dry Bags from Nicki's Diapers!
(And they're from Madison!)