Adwords has lowered minimum bids for site targeting. Now one can run a campaign for as little as $1 CPM.
I just decided to try this. However, I thought $1 was high considering the unknown variable. If I get a 1% CTR, I am paying 10 cents a click, HOWEVER, many sites have their boxes all over the place. For this test a cost of 20 cents or less per click is acceptable. That means I need a .05% CTR. We'll see.