If you want to buy an airsoft pistol, then here are some tips that you should read before buying anything. First of all, you should set a price range. There are cheap spring pistols that only cost $5, but you know the saying that you get what you pay for.
On the other end, there are some electrics and gas blowback pistols that will cost $200. If you are going to get an electric or gas pistol, then I would personally recommend spending a minimum of $50.
If you are on a tight budget though, there are several good spring pistols for around $20. Another good way to start your search is by picking what type of gun you want.