Here's what I've found to be the bare minimum:
dark closet OR room OR changing bag
bottle opener
scissors
tank and reel
clock with seconds display
a couple of graduated jugs (can be cheap ones intended for kitchen use)
Your choice of developer and fixer*
Kitchen or bathroom sink
Massive Development Chart
http://www.digitaltruth.com/devchart.php
A thermometer for the liquids is nice but not essential. You can also mix them ahead of time and let them come to room temperature.
An old apron and a supply of nitrile gloves, depending on how much you value your clothes and how nasty your developer is.
*If you don't think you'll be doing a lot of developing, get a liquid concentrate developer (such as Agfa Rodinal, Kodak HC-110). These you mix up only as needed and the concentrate keeps for a very long time.