The same gun was made for the Germans in 7.65mm Browning, or .32 ACP. The original Hungarian gun (as shown) was in 9mm Browning Short (.380 ACP) but the barrels interchange, so make sure which caliber it is before buying ammo. They are very sturdy and reliable guns.
That one is a nice collector's piece as many seen here are the ones made for Germany with the "jhv" code instead of the full markings. The trigger guard mark is the Hungarian crown military acceptance stamp. Top value is around $375, less with a reproduction magazine, which is all that is available today without a lot of time and patience spent looking.
Edited to add:
The slide markings translate as Frommer Firearms and Machine Factory, Ltd. It was in Budapest. The same factory is now producing the quite good FEG line of pistols, including a BHP clone.