Well, since this was posted in the handgun sub forum, one would assume that the OP is looking at buying a handgun.
This still leaves the question as for the use of this firearm. Handguns are poor "man stoppers" in general and there are certainly better choices for a dedicated home defense firearm. Let's assume for a moment that this handgun is for carrying.
The standard reply to such question is: Go to a range that rents handguns and try them out. Take a basic firearm safety and handgun training class! Hands on experience with a professional firearms instructor provides you with safe firearm handling practices and with basic background knowledge about firearms in general and handguns in specific. After all, you wouldn't buy a guitar and call yourself a musician without having any training and practice either.
For your budget, you need to include said training class and rental fees. If you purchase the handgun at the same place where you did the training, you may be able to get a discount. The budget should also include target ammunition for practice, self defense ammunition, a decent holster, a decent belt, some cleaning tools and solvent, and some additional range time for practice (several visits, potentially an annual membership). Oh, and the handgun, obviously.
With your first class and your few practice sessions, you are now at the stage that you can play basic riffs on your guitar, but not full songs. Take a defensive handgun class that is designed for people carrying handguns. You will learn a lot in such class, such as how to carry the firearm, how and when to draw it and fire it, how and when to reholster it, how to shoot fast and accurate, how to shoot while on the move, how to shoot at moving targets, how to deal with different scenarios, one-handed shooting (strong and weak hand), cover vs concealment, properly taking cover, etc.