I haven't really been looking around much, but I've really only seen them online.
I hope to be ready to at least start out with a small juvenile within the next year or so, but it really depends on getting a job when I graduate. My girlfriend brought it up again tonight how much she wants stingrays and I warned her again how huge of a tank they'll need (I said my current plan is 96"X48" or so) and she said she doesn't care as long as it's clean (which is basically a requirement for rays anyway), so my eventual ray keeping/breeding project is greenlighted, but how quickly it takes off is still completely up in the air. I would definitely be in for a group order, but not in the very near future.