Same basic idea as the 37signals one: $300 buys you a 30-day job listing. If you're a GitHub user, you can opt into seeing targeted job listings on your dashboard by marking yourself "available for hire" in your account settings. Targeted based on what, you ask? Remember, GitHub has your code, and they know what languages you use. They also know where you live. Can't say yet if it works, or how well, but it's a promising idea.