If you are really serious about turntablism, it doesn't really pay to get cheap turntables. You won't be able to do tricks properly without the record skipping. Try to find a used pair of Technics MLK-1200's turntables. They are pretty much the standard. You "might" be able to find a pair of used for $300 each. Brand new they come at $500 each. But they will last you forever.
As far as a mixer, you don't need a top of the line one. You can get a cheap Gemini mixer. They have a "decent" cross fader for tricks. You can get a replacement for like $35 I believe.
For records, there are several "scratch" records designed for turntablism. DJ Rectangle Ultimate Ultimate series are really good, I recommend them. Also, Dirtstyle or Super Duck Breaks is a classic.
Good luck. if you can't afford Tech 12's turntables, at least go for some that are direct drive, not belt driven.
