The iPhone 4's antenna issues make using a case almost imperative for many (left-handed) users. Unfortunately, Apple has decided not to give their $29 bumper out for free. This decision leaves an entire market open for better, cheaper solutions. We've told you about a few of them already, but if you still feel you shouldn't have to pay for one, there might be a better way.
Indeed, Cases.com is running a little promotion these days where they're giving away one of their cases for free. You'll still have to pay for shipping (which some suspect is how they finance it). Anyway, at $3 a pop, you're not taking much of a risk, and it might at least improve your reception.