Still the best source for buying and selling used Macs, BeamEcho (formerly CPUsed) began life operating out of a converted garage. How times have changed: a showroom now displays the full line of new Apples, with a second space for iPods and accessories. New equipment isn’t particularly cheap, but the second-hand stuff is a steal. For example: a 12-inch 1 GHz G4 iBook could recently be had for $499; a G4 tower costs less than $350. On one visit, a 1-terabyte external hard drive was selling for $369. Check the Web site (www.beamecho.com) for the latest prices. Repairs remain a core service.