Building relationships with other businesses

I am working on adding additional clients to my business. I am going to approach some fitness equipment stores to see if we can get an agreement. My proposal to the fitness stores would be this: They sell a piece of cardio equipment, free weights, home gyms, etc. They notify their customer that with their purchase they get a free consulting and workout with a personal trainer (me). I see this as beneficial to both parties as they can give their customers something different than other stores are currently doing and I get potential leads. Is there something I might be missing in this effort? And is there a certain way you would approach the stores on this?

Thanks,