I personally don't think seahorses should be purchased at a LFS. Try Draco Marine or Seahorse source. Both have Erectus and have steller reputations. I believe you can get them from either place for around 65.00 each. The best thing about buying from them is that's all they do is breed and raise seahorses. They are bred and raised in their tanks, healthy, and ALWAYS eat frozen mysis shrimp. Not to mention the fact that they have been taken care of properly since birth. You know where they came from, where they've been and have all of their history. No taking any chances. Both have excellent customer service and you can call them for help if you need it.
Good luck with you seahorse adventure. They are even more addicting then reef tanks, lol. Once you get the tank ready for them make sure you can keep the temp. under 72. Higher temp. can lead to bacterial infections. Been there and learned the hard way.