It depends what type, but I found a Hi-point compact 9mm pistol for $145 plus tax.
The 9×19mm Parabellum (abbreviated 9mm, 9mmP, 9×19mm or 9×19) cartridge was designed by Georg Luger and introduced in 1902 by the German weapons manufacturer Deutsche Waffen- und Munitionsfabriken (DWM) for their Luger semi-automatic pistol. For this reason, it is designated as the 9mm Luger / 9mm Luger +P by the SAAMI and the 9 mm Luger by the C.I.P. (differentiating it from the 9mm Makarov and 9mm Browning cartridges). Under STANAG 4090, it is a standard cartridge for NATO forces as well as many non-NATO countries.
The name Parabellum is derived from the Latin: Si vis pacem, para bellum ("If you seek peace, prepare for war"), which was the motto of DWM.
A semi-automatic pistol is a type of handgun which uses a single chamber and barrel, with a mechanism powered by the previous shot to load a fresh cartridge into the chamber. One round is fired each time the trigger of a semi-automatic pistol is pulled.
A revolver, which uses multiple chambers and a single barrel, and a derringer, which uses multiple chambers and multiple barrels, also fire one round for trigger pull, but achieve this in different ways and as such are not classified as being semi-automatic.
The Beretta BU9 Nano is a semi-automatic, striker fired, micro compact pistol line manufactured by Beretta in the USA at its Accokeek, Maryland facility. The initial design was created for a .40 S&W round but the initial release is chambered in 9mm. It has been available since October 2011.
The Nano is designed as a compact gun for concealed carry. It has a technopolymer frame and a Pronox finished slide. Pronox is a nitriding finish similar to Tenifer (as used on, among others, Glock pistols) and Melonite (as used on, among others, Springfield Armory XD and Smith & Wesson M&P pistols). The sights on the Nano are low-profile 3-dot sights. It is currently not available in California.
Hi-Point Firearms, also known as Beemiller (Distributed by MKS Supply), is a firearms manufacturer based in Mansfield, Ohio. However only the CF.380, C9 9 mm, & the carbines are made in Mansfield. They manufacture low-cost pistols and carbines, in the following calibers:
Hi-Point semi-automatic pistols are polymer-framed and generally regarded as simple, inexpensive handguns, which trade-off aesthetics for lower manufacturing cost. Based on a simple blowback design, Hi-Point pistols do not have a breech-locking system like most handguns. Instead they have large, heavy slides that hold the breech closed through sheer mass. The result is a heavier gun, for its size, that is bulkier and may be less aesthetically appealing than designs employing recoil operation. Pistols that use a blowback action in the calibers that Hi-Point firearms are chambered for are somewhat rare. While making the pistols heavier, this design also makes them mechanically simple and easy to maintain. Hi-Point recommends hosing out the action with a powder solvent like Break Free Powder Blast, Rem Oil or another aerosol solvent, then every 300-400 rounds running a cleaning brush through the barrel.