Easy answer to your question, go to a local gun shop and look at a few. Different guns will your hand differently. See what gun you like and can handle well. Check local pawn shops too, you can find some deals one guns from time to time. Right now, handguns sell fast, at least around here.
If you order form Gunbroker.com, they have to ship to and FFL dealer and you have to pick out an 4473 gun form and have quick background check. I do those forms pretty much everyday, takes about 15mins to fill out and have the shop call it in to the ATF.
You might be able to find a nice gun in the $300-400 range, but stay clear of stuff like Hi-Point.
The S&W SW9ve might be a gun to look at, not exactly top of the line but it will be ok for plunking.
Taurus makes some nice budget friendly guns too. Look around and you might find a Taurus PT92 9mm (Beretta 92fs clone) in you price range or a little above. Hard to beat a 92 for a budget 9mm.
If you want to put up a little more $, the Glock 17 is a nice handgun, but I really like my XDm40. You really need to see what fits your hand.
Forget the 10mm, if you want more stopping power get a +P capable .40cal. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
EDIT:
Oh, and if you are looking for something for home-defense. Forget a pistol, get a 12ga and load it w/ #6 long-brass. Fire that in a house, you will stop anyone you need..but it will not rip thru multiple walls in your house.