There are a lot of good bike greases. Park's PolyLube and Phil Grease are two well known ones.

Why the emphasis on cheap? How much of any grease are you going to use? I bought Phil Grease in a 22-oz tub for about $20 and it will last for years even though I maintain 6 bikes. Buy a Duelco grease gun and refill it from the tub to keep the remaining grease clean.

If you insist on cheap, get a tub of white lithium grease at any auto supply store.