My free plecostomus I got a year or so ago. He wasn't specifically free... we just bought a tiny 15L fish tank to put some shrimp in, and when we filled it with water he appeared ๐ณ
I'm guessing he was suckered on to the piece of driftwood and had enough moisture to survive the 48 hours or so between the seller emptying the tank, and us refilling it after buying.
Dudes fair bristly. A heck of a lot bigger now than he was when he appeared in the tank, not all that much bigger than the neo shrimp that were his tank mates.
You will need a really big tank, they get really huge, and territorial but I find them really cute.