If you want a functional one I actually reccomend this one as it's universal size, cheap, compact, and simple. The only downside is that there's no voice diaphragm.
https://www.ebay.com/itm/233362859323
I reccomend these filters, they're rated A2B2E2K2P3 (highest protection that is practical to have) and they're relatively cheap compared to other ones.
https://www.ebay.com/itm/363074281067
If you just want one to mess with your friends or for halloween I reccomend an old soviet surplus GP-5. These have filter threats that aren't modern and the filters they come with have asbestos. If you don't use the filters, it should be fine.