Hi erk628
If you are looking for interesting fish, before you do anything else, I would suggest you check our list and see if there is a local aquarium society in your area. You would be amazed at the variety of fish that can often be purchased at their monthly auctions or traded from other members. They will not only be healthy but will have been raised in your local water supply.
http
/www.fishforums.net/index.php?/topic/292232-local-aquarium-society-directory/
As for online purchases, I like AquaBid. If you read the offers in the areas you are interested in you will soon get a feel for what the main sellers are like. Pay particular attention to the feedback. Fish hobbyists seem to be serious about this and, while you can allow for problems to happen once in a while, most of the comments will be pretty accurate.
When buying from AquaBid sellers, note if they are breeders, importers, etc. Wild caught fish will be different in age, size, and condition from tank raised fish. You will be taking more of a risk but it's often the only way to obtain unusual species.
It's a good idea to contact the seller and ask a few questions. Most will answer you promptly and completely. They want you to be happy with your purchase and this means helping you get your expectations in line with what they are selling. Most of them are friendly and helpful. Forget about doing business with the few who are not.
Shipping makes a big difference too. With the cold weather you will need to find someone who ships with heat packs and use overnight delivery. This is expensive and a good reason why you should buy the more common fish locally.
As for the big online companies, I only had experience with one of them and it was bizarre. Here's my thread about it:
http
/www.fishforums.net/index.php?showtopic=112379&st=0&p=946404&hl=raising%20the%20dead&fromsearch=1&#entry946404