I would highly suggest you go to a certified firearms course, this way you can get good information on what you would like best, and you will know much more about firearm. Now with that said.
Probably the most well known budget pistol on the market right now is the Smith and Wesson Sigma. In the 9ve 9mm configuration, this pistol can be had for less than $300 with currently available rebates. That leaves $100 which can be used to buy 500 rounds of practice ammunition or accessories like additional magazines and holsters. Of course the Sigma is not without its drawbacks – the trigger pull has been rated as “poor” by a number of reviewers who claim that it is nothing more than a poorly executed Glock knock-off. We feel the Sigma is a fine pistol for its price point, it certainly is reliable, but better options are available for our $400 budget.
One of the most popular budget pistols is probably the Ruger P95. The P95 is well known as a utilitarian pistol. There’s nothing fancy about it, it works reliably, and it’s easily serviceable. It also met his requirements for having an abundance of accessories and holsters available. We also looked briefly at the Ruger SR9, but decided that like the Sigma, the trigger pull was just too hard and gritty. Additionally, accessories for it were not widely available enough to seriously consider this pistol.
Kel-Tec has a number of reliable and inexpensive pistols, one of which is their new PF9 model. The PF9 is a compact and very slim pistol, perfect for concealed carry. The PF9 is very slim, at less than an inch thick. Despite its small size, it still packs a wallop with a 7+1 capacity of 9mm cartridges. The action is DAO and the trigger pull, while long, is smooth and consistent. The PF9 is also very inexpensive: MSRP is around $300, and it can often be found less than that. It may however be too small to use in competitions like IDPA, which the brother-in-law has expressed an interest in participating in.