I have tried MP-68's and Titleist 710 MB's (the newest and 'greatest' from two top blade makers)...hated them. I tried the Ping S57's and loved them...they will definitely be my first set of tour irons once I have the funds. I suggest trying everything you can get your hands on. You can find older versions of all 3 of these models for cheap. I know for ping the older model is the S59 (or the S58 if you want a little newer, the numbers go down as time goes on). I'm not sure what the Titleist and Mizuno models are.
Taylormade r5 - $50
http://www.3balls.com/product-produc...RIVERS-RH-USED
Titleist 983k (my favorite model, it got stolen) - $50
Aldila Shaft
http://www.3balls.com/product-produc...RIVERS-RH-USED
If you've never bought from 3balls.com, you will not be disappointed. Most of the time the clubs are better than described.
I play $3-4 balls because you pay for consistency of spin. Although from what I hear the Bridgestone balls are making it happen for $2.50 a ball or better.