Well management systems and not kill your pocket hardly go together. VEMS in my opinion is the most affordable, highest quality unit.
I think you can get megasquirt slightly cheaper, but it lacks a lot of quality for little savings.
AEM and Haltech are probably the next best option. Vi-Pec, Link, and DTA are good too.
Cheapest option and less frustrating option is have someone like Barry at Midnight Tuning hook you up. Ask him what he recommends and build to that. It will be the best bang for the buck and the least amount of work.