The Vic 20 was like the economy version of the Commodore 64 (funny that they needed an economy version of the C-64, my dad bought one new for $100 when it came out, heh today new comps are like $3k) i believe the Vic 20 only had 20k of ram (1/4 of my cell phones ram now) it was also supposed to be a more user friendly version of the C-64, for people who were not as coputer savvy.
I have two old commodore 64's now, i dont think either of them works though. For an 8 bit CPU that only ran at like 1.5 Mhz, it sure had some awesome applications/games, amazing how much a little chip can do when it doesnt have to spit out a GUI. The sound capability on the commodores was way ahead of its time.