Guerilla Marketing

Guerrilla marketing, as described by Jay Conrad Levinson in his popular 1982 book Guerrilla Marketing, is an unconventional way of performing promotional activities on a very low budget.

Stickers

If you are trying to reach people who ride, there is no better place to do it than the places they park their bikes. There are certainly others printers, but Contagious Graphics can produce outdoor vinyl stickers with permanent adhesive that won't fade for 3-5 years in direct sun. For $25 you can permanently flyer 250 bike racks street posts and the like around town.

Since you will probably have contact information on the sticker, you may want to consult some property owners before you do this.

A 4.25" x 1.38" also works great on top tubes.

Here is an example used in a similar fashion for the Salt Lake City Critical Mass

Local Retail Bike Stores

Build bridges, don't burn them especially when it comes to your local retail bike store. They can be an incredible referral as well as a great place to put your flyers and posters.