You could always talk to the manager first. I thought about it. I think I'll try and strike a deal with the store manager of my LFS if I sell him some of my fry. Something like: with every fry you sell, you have to give out this print out (hands said print out of betta keeping). I'll give the same print out to people who purchase off aquabid, etc. Though most stores don't take too kindly to you hanging posters up, so I wouldn't advise it. You can actually get yourself permanently kicked out that way. :(
What had you sad yesterday?