I work part time in a store and a thought occured to me, why not use a system that is already in place to cheaply market REI services to the people in town. Our store as with many of the other grocery stores in the area has ads printed on the back of all receipts. Whether a person is spending $1 or $1000 they are walking out with ads in their hands on the back of their receipt. A regular customer that owns a small pet shop across the road inquired about it, I gave him the info and he signed up. I would guess if his small store can afford to use this service it is inexpensive to use. The ads are also targeted, they sell to businesses in town and your ad will only be used in stores that are in your target area. Not sure if this company is nationwide, if its not try finding one like it in your area.
Here is the company’s website: http://www.fanfaremedia.com/register_index.cfm
http://www.fanfaremedia.com/images/image_register_sample.jpg
Disclaimer: I have no vested interest in this company, I am not an affiliate nor am I am employee of the above mentioned company.