I set up a full darkroom for under $50. I paid $20 for an enlarger, 6 trays, and two 1L air-evac bottles from Craigslist in Myrtle Beach (I'm from Charlotte, NC, but was traveling to Myrtle so checked out their CL).
I bought two steel tanks, an easel, an old Time-O-Lite timer, two 35mm reels, two 120 reels, a large assortment of film clips and print clips for $25 shipped from a user on another forum.
I bought an array of plasticware from the dollar store for developing film and prints. Three 1/2G jugs, a cat box tray, and a measuring cup from my dollar store.
Oops, that's $50 now and I didn't include the thermometer or the glass measuring cup I bought for finer measurement. Those also came from the dollar store.
So, I figure I spent about $55 when it's all said and done for everything after tax and such.