Here our pet stores have them. I know due to recent problems I'm paranoid but quaranteen them for at least a couple of weeks and use parasite dip before adding to pond. Don't want to see anyone else go thru what I've gone thu past 2 weeks and it ain't over yet. My old snails were in first pond that got sick so I treated them also.
i was looking at ramshorn snails from someone named fishfarmerjohn on ebay, his rating is 100% positive and prices seem reasonable, but was sort of hesitant just because it is ebay. however his shipping charges are way better then the few vendors i found online.
i was going to put them in small pond first and then gradually add to large pond with turtles, so i will definately quarantine them for a while.
dont know if the turtles will eat them all and i should keep some in the small pond in hopes of more snails, or eventually add them all to big one. this is such a new thing for me, just started these last summer cause the turtles outgrew their tank. it is so cool to watch them in a pond setting.