Shopping bag advertising

I went into town the other day and picked up some things for a new marketing campaign idea I have. I purchased some of those canvas shopping bags, a package of iron on transfer material and a package of printer cartridges for my printer. Now I am working on ideas for advertising for my websites that I can place on the sides of the shopping bags.

I'll create large sized iron-on printouts for the websites, and iron them onto the sides of the shopping bags. That way when I go to the store people will see advertising for my websites.

I have also been thinking this would be a good way to do advertising in general, but I'm not certain on just how to sell the ad space on the shopping bags. I can see where it would be a great way to get out business information, though, so I might talk to someone with one of the advertising sites I know about starting up a "Green Ads" deal where advertisers pay so much for people to print out ads that are ironed onto their reusable shopping bags with the size and placement of the ad determining the cost of the thing.