You buy gift cards with other purchases and pay people under the table. The gift card is cash-like for stores like Home Depot or Walmart.

You can also do stuff like get paid with someone else’s Cash App (like grandma’s) and then buy gift cards with it. If you hire “independent contractors” for casual labor or construction, many of them do that. The gift card transaction is just another CVS/Mobil purchase.

It’s not just tax evasion, sometimes they are avoiding child support or garnishments. Other times folks are just unbanked for some reason. You get blacklisted from banking you do something stupid.