I bought a solo ad from Sophie Choung for $30 for 100 clicks or $0.30 per click.
She promoted a site of mine called Simple Internet Marketing Formula which on average converts at about 33%.
I got 118 uniques (18 extra) and 22 optins for a conversion rate of 19% and a cost per subscriber of $1.36
You can buy a solo ad from her here
Have you bought a solo from her? Post your review below.