I just tea dyed my Wal-mart curtains. I actually bought the curtains at a thrift store brand new and my friend told me they were from Wal-mart. They were stark white and I don't know why I thought they would be perfect in my front room, which has no white in it. But then I thought, "Hey, can't I just dye them with tea bags?" Well, I looked up how to do it online and was disappointed to find very elaborate instructions that were way over my head (or I just didn't have the patience for). Some of them involved overnight baths, that sort of thing. No thanks. So, as commonly happens with me, I threw caution to the wind and went for it---instructionless. It turns out it could not be simpler.
I boiled about 1.5 to 2 gallons of water in my biggest pot. Once the water was boiling, I popped in 6 bags of decaf tea. Just regular Lipton. No special flavor. I kept the water boiling the whole time, but I took the bags out after about 2 minutes. Then I just dunked one curtain at a time. These are cafe' curtains, so they aren't big. I kept each curtain in for about a minute, since I wanted them to be off-white, not tan, and certainly not brown. This turned out to be the perfect amount of time. Once I rinsed them out with cold water, I put them in the dryer. It was weird how wrinkly they came out since they were a poly/cotton blend, but mostly poly. 
Anyway, they turned out perfect and I am very happy with the results.