You would be surprised how far a few hundred dollars spent on Adsense can take you. It might take a little bit of practice before you figure out businesses that are worth advertising but when you do -- you can get leads that pay 1000 - 100,000+ times what you're spending on Adsense (and even repeat customers.)

This is probably quite ordinary advice but as someone who hasn't done that much marketing before -- I am still blown away by how effective search engine advertising is. I feel like with just Adsense I could make virtually any website profitable as long as it was cleanly designed and the margins were high enough. After that, its really just rinse and repeat. Maybe throw in some promotion on a few other channels and you've got yourself a solid business.

Advertising is practically modern day alchemy.