looking for online source for heartguard plus

I Stopped buying hearguard plus at the vet because it was so expensive, last year, Now they won't sell me any at all regardless unless I have all the dogs tested for heartworms, I never let their heartworm lapse instead, bought it on the internet, or asked those on ebay who were selling their flea and tick if they had heartguardplus, I've lost my supplier's name, that allows me to buy heartguard with out a perscription, does anybody have an online source for heartworm without a perscription, I have 8 dogs, I am not going to have them all tested, when I know for a fact i've never let their heartworm lapse, any help would be appreciated, Iknow i'll find a source sooner or later, I thought i'd ask those of you who have lots of dogs, where youget yours at, and it's important that I can get it without a perscription. since I don't have a perscription now with out having them tested.

kathy_ann