when etoys put their barbie digital cameras on clearance for 7 bucks, I bought about 60 and sold them for an average of about 35 bucks profit each.
also, i remember some no-name site selling infity BU-120 subs for 140 shipped, I bought a few and sold em for about 300+shipping on ebay. Also, amazon had a TIVO sale (14 hour units for like 99 bucks), I bought a dozen and sold them for about 250-300 each, I think.
hot deals were my main source of income my first two years of college.