what are some cheap, but high quality headphones that I can buy. I will use them mostly for mixing. I don't want to spend a bunch, but if I have to I will wait.
Disregard Bruce's advice at your own peril. There are some things that headphones do very well; mixing is not one of them.*
*SOME engineers CAN mix using just headphones, but it takes years to learn how to translate what you're hearing thru phones to real-world compatible mixes.
So how's that gonna work for you? Waste a lot of time doing a whack of shitty mixes on headphones because you'll find it almost impossible to overcome the translation curve without significant experience under your belt, only to have to revisist them later when you actually do get monitors?!?!