There are so many sites that offer buying and selling ads (eg. tnx.net inlinks.com teliad.com etc). Which is the best?
IMO,there is no the best. But it more depend on the quality of your site. If your site have quality that meet the buyer requirement,they will buy it from you.
How about selling your ads yourself. With some persistence, you can find advertisers and keep 100% of the profits. Just make sure you invest in a decent ad serving solution that is easy to use for your advertisers, lets them see the results of their advertising dollars (amount of clicks, etc.) and it should be easy for you to manage. And by easy I mean automatic so less work for you. If you have a quality site, this can work out better for you in the long run.
You can use blackhat software to actually get your links for you. No need to pay $1-$10 per link on a website when you can get them for free
I just went to sign up for LinkAdage and they actually ask you for your SSN, that is very suspicious, what is the deal?