I made about $800 last year in e-book sales. This is without an advertising budget at all, strictly making myself visual and vocal on various web sites (like this one). 2008's high point was Read an E-Book Week
, good PR for me, wherein I made about $400 of that in one month.
(Important note: My novels were in the Kindle store during 2008, but only made about $150 for the year. Due to such a poor showing, I've pulled them all.)
Based on past sales I believe that money spent on advertising would significantly improve these numbers... I just haven't had the ad money to spend, though I was originally hoping to be able to start at the beginning of 2009 (pesky economy!). At this moment, it looks like 2009 sales will not match or exceed 2008 levels without investment in advertising.