Check out rimfirecentral.com. There a few forums dedicated to the .17HMR and HM2's. Someone there will be able to tell you where the cheapest ammo can be had. Probably already a post on it. Look in the 17HMR ammo section. They update it whenever a big sale goes up somewhere.

It's also just a great sight for anything rimfire. I couldn't tell where to order ammo though. I just get it at the local gunstore or Cabela's.

Paul