Joel,
Its a hard call what to say about foam tire prices. I have gotten to the point where I cut my tires brand new down to whatever size I think my car works best at. I just dont see value in starting them at 1.90" for example and having my car not handle as well as it could till they wear down. Chances are they will be peeling off the rim long before they get to the optimum size. The side loading on the cars now is very high. I am sure a stock 12th is as fast as a mod 12th was years ago. With new battery tech-were driving the piss out of them for 8-minutes now too. GOne are the days of 3/4 throttle in stock for 7 minutes.
For sure if you your budget is as important as ultimate performnace-there are definate ways to squeeze more life out of your tires. Use a harder compound or a more exotic blned that usually have less grip, but longer life. Cut your wheel wells bigger so in crashes your less liely to cut a tire. Drive less aggresively and make sure your set-ups are always good, meaning not tight because tight cars wear out fronts and tear apart rears. Also-and I am NOT one to preach not hitting anything, but drive more conservative lines.Thats about it for me,
Ray