In an ideal world, I would not be writing this article because you would take it upon yourself to pour over reviews and data relating to the firearms that best fit your needs and budget. This is not an ideal world, however, and you need to be spoonfed recommendations because you would end up buying a Taurus if no one told you not to.
In the following article, I will lay out some options to consider based on your budget. If at all possible, I would suggest saving up some money to spend on a handgun because if you can hold off for a while and have $400-600 to spend rather than $100-300, you can get an all-around nicer firearm. The difference a few hundred dollars makes is significant. That being said, there are still some fine options for the budget-conscious gun buyer.
[I had planned on sticking solely to brand new firearms chambered in 9mm, but that would generally rule out the poorfags who cannot spend more than $200, so I will throw in used options/surplus arms in various calibers]
There is nothing down here. You might be able to find a well-worn .22 LR revolver on the used market, such as a Heritage Rough Rider, but it will not serve you well in any defensive role. The only way you will find a decent gun under $100 is if a meth head is willing to sell you a stolen one in exchange for chasing away the spiders that are plaguing him/her.
If you intend to carry at some point and would entertain the idea of a pocket gun chambered for an anemic cartridge, the Ruger LCP just might be for you. It is tiny and uses .380 ACP, priced typically between $169-219. The .380 cartridge is less than ideal for a defensive handgun, but with the right ammo and good shot placement, it can serve as an okay option (which can be said of any cartridge really). This gun is incredibly concealable due to its tiny dimensions, but it sacrifices ammo capacity as a result, capable of holding six rounds in the magazine plus one in the chamber.
Beyond the LCP the only other options in this price range will be surplus handguns from combloc countries. The 9×18 Makarov and 7.62×25 Tokarev cartridges are capable rounds for self-defense but may be more difficult to find on the shelves of your local ammo retailer and a little pricier than the ubiquitous 9mm Luger. Surplus pistols that fire these rounds can be found under $200 occasionally, but as the supply of available surplus dwindles, the prices increase. As a matter of fact, I looked up the Zastava M57 and the Polish Radom P64 and both are currently over $200.
Additionally, the Star B 9mm is still available at $199 in most cases. I have heard mixed, but generally positive reviews about it. As with all surplus guns, be aware that finding parts and spare magazines may be difficult.
This is where you start to have a few more options. The guns in this price range are the bottom dollar models from their manufacturers, however, they are still generally reliable and well-built despite their lack of comfy features.
Basically, all of the sub-compact Ruger firearms fall into this price range. They will be small, low capacity, and kind of ugly, but they will work. The LCP, LCP II, LC9S, etc. are all aimed directly at people looking for low priced concealed carry options. They are not the best for the job, but they are not terrible by any means. And if they do not work you can usually rely on Ruger's customer service department to get you taken care of.
Also from Ruger are the SR9E, and the newer Security-9. With 17 round and 15 round standard capacities respectively, they will literally give you more bang for your buck than the sub-compacts listed in the paragraph above. They will be harder to conceal, but they will probably be more enjoyable to shoot, and more sufficient in a self-defense role.
The Smith & Wesson SD9VE has long been the ugly cousin of the better handling and higher priced M&P line of pistols, but what it lacks in aesthetic value, it makes up for by being a cheap date. If you cannot get over the reportedly unpleasant trigger-pull, there are now aftermarket triggers and parts available from Apex Tactical that should make it actually kind of nice to shoot.
There are some guns such as the S&W M&P Shield 9mm, Canik TP9SA, and others that will occasionally drop below the $300 mark when they go on sale or have rebates available. Also, finding police trade-in M&P pistols in .40 S&W for around $300 on Aim Surplus is entirely possible, though 9mm variants will likely go for more money. If a sale lines up with the timing of your purchase, you should strongly consider these as options.
I am sure I missed some guns that would be considered decent choices in this price range, and I am sure that some may take umbrage with what I did include. Sound off in the comments. If you have questions that you think I might be able to answer feel free to contact me.
As I've said before. Rent some guns at a range and go with what fits you best. These articles are meant to provide some semblance of an easy-mode for picking your first gun. The final decision is up to you.