Well, if you're anything like me, you'll buy a good or decent quality headset and still scoff at having the bike shop press it in for you. There's really no good reason not to spend that $20, so my recommendation is either to camp out for a bit, watch Craigslist and ebay, waiting for a King to come up cheap, or try a partial trade if your funds are limited. Don't skimp on the install. If you're pounding the new headset in, you're defeating the purpose, just my $.02.

I bought a King on CL for $40 and paid my LBS $15 to press it in, remove the crown race, and adjust the tension. Money well spent. Years ago, I bought a crappy cheap Cane Creek thing and pressed it on myself. Spent $32 total, and it worked. NOTHING like the buttery smooth action of the King though.