I've tried it and just invested $10 into advertising and only got about 56 clicks for it with a really lousy CTR, something like .12%, however it's great to advertise your website if it's a bit more mainstream, I myself have a webcomic and get about 1% click through rate for about $.009 a click. It depends what you need it for.
Hi, I've started with $10 and until now I haven't withdraw or invest more money. I try to balance what I make with what I spend (also as a projectwonderful advertiser). The ad placement and the kind of ad is important to get clicks, for insteance: a well placed skyscraper can get a good number of clicks. Regards, José