The cheapest universal programmer that I know is the gallep, from batronix (http://www.batronix.com) that cost US$288, but they only sell it, they don't put the schematics on the site.

At the Batronix site you can find a EPROM and EEPROM programmer circuit to build yourself.

For MCU's I don't know nothing universal AND cheap. I think the best approach for you is to build the MCU programmer on a "what I need now" basis, but in the long term it can be more expensive than the commercial version, if you need to build newer programmers often.