Handguns are all not the same; there are various factors that go into determining what handgun is right.
Of course the important factors vary and really should pertain to the individuals situation. Some factors to think about include cost, accuracy, caliber, and reliability, grip or feel.
The first and foremost factor for most individuals is cost. Handguns vary in price quite widely. A small caliber handgun can go for as little as two-hundred dollars while a collectors version can go for a bit more; cost is almost always the number one factor for any purchase of this magnitude. A bargain handgun should not be looked at as there is a reason, normally not give to the purchaser, as to why the handgun is priced to sell.
Most handguns will not have a problem with accuracy. The one thing to consider is if you, the purchaser, will have a problem with a handgun for accuracy; meaning each individual reacts or handles a handgun differently so what might be accurate for a veteran handgun owner might not be the best choice for you. See if the store has a range where you can test out something similar if not the actual handgun where you interest lies.
There are a variety of caliber handguns on the market. A larger caliber has much better and greater stopping power but might recoil more than you are willing to take; especially for someone not familiar with the use of such a weapon. However, the smaller caliber might do what the handgun is intended for; to stop an intruder for example but the recoil is much less. Budget plays another factor in this decision.
How reliable is the handgun your thinking about purchasing? Does it do what it is intended for, to stop an intruder? Read the manufacturers thought about the particular handgun your thinking of purchasing and better yet do research online to get reviews of the handgun by people like yourself! The more knowledge you have the more relaxed you will be about the purchase.
Grip or Feel
It is very important that you feel comfortable holding the handgun and using it. Again, see if the store has a gun range so get a feel for the handgun. The more comfortable you are with the handgun the more confident you will be if and when you want to use it.