My first con in 2010 cost me maybe $40 total for a Jedi robe

I made it from a brown bed sheet and a rope belt. Back then, I thought that was the only way to do it cheap. About five years ago, I found a local thrift store that sells old curtains and tablecloths for fabric. Now I can make a full pirate coat for under $15 using a heavy curtain. The material is way better and looks more real. I still use bed sheets for some things, but having more options changed the game for me. What's your favorite thrift store find for a costume base?