I managed to sell some ad space at two of my sites for a whopping total of $250 per year. This is my first sales ever of online ad space. I did not find the advertiser but rather the advertiser found me.
After some haggling over the price ( I asked for $240 for the first site. This was bargained down to $150. I offered the 2nd site at $150 and this was bargained down to $100) So that is how the $250 sum came about.
The ad space was just a small one as it was mainly a text ad of less than 20 words.
Perhaps this is a start to me diversifying away from Adsense.
As a tip to bloggers out there, make sure you have a price list ready just in case advertisers start knocking on your door and you have no idea what is the "correct" price to ask for.