There are some good cheapies like the Old Standby, etc., that come only in the key of C, but are good "professional" quality harmonicas. I personally think beginners on a budget are better off with a cheapie, because they usually ruin them from poor technique. By the time they've messed it up, they have a good idea whether they're serious about it, and if they are, then investing in a good harp such as a Lee Oskar makes sense.
If a little extra cost isn't an issue, and/or you KNOW you're serious about it, you can't go wrong with an Oskar. I think they're easier to learn on (but I've been playing for 40 plus years and have to go on others peoples opinions on this one - my students like them), and they outlast by a wide berth any harmonica made by any company that begins with an "H" or "S" :-) (I think that covers 'em all :-)