I'd recommend a M11/9. By itself, not a great gun, BUT it is now a modular platform that allows you to put different uppers, stocks, optics, etc. on it. You can get several 9mm slow fire mag and drum fed uppers, and you can get a 5.56 upper. I've got both and they are reliable and very fun to shoot. One of the 9mm uppers allows different rates of fire to suit your preferences.
You can buy the gun plus accessories, a couple of uppers and ammo today at your price point. Later, you can expand and buy more uppers. Having the flexibility to use the same platform for good 9mm and 5.56 (or 300BO cal - change the barrel) doesn't come again until you get into the M16 or HK sear platforms. Both of those options start at ~2x the price of admission with the M11/9 option.
I predict a beltfed upper for the M11 / Mac family will eventually come along. The 9mm slow fire upper I have is an excellent shooter.
You'll want to add suppressors at some point.
Other options:
Sten - you can get a tube gun well within your price, maybe even a c&r actual wartime gun (top of your price point). If you want history, then this may be your choice. Different configurations are available including the MK5 (?) which has a wood stock.
BRP ‐ possibly several configurations in your price point. I've never shot one but have heard great reviews. Drum options available.
AC556 - factory 5.56. Very fun to shoot. Stainless, blued, full stock long barrel or shorty folding stock. Good. 22 kit (Ciener). Lots of folks look down their nose at these since they're "not an M16". Well, they're not, and they're priced accordingly.
Uzi - bolt or conversion. LOTS of spares available. Iconic and easily recognized. Fun to shoot. Can find .22 and .45 cal. conversion kits depending on gun you buy (how was it converted). Stretching your budget - you may need to add some $$.
MK760 - mags very easy to load. Faster rate of fire. Actually a fun gun to shoot. Copy of the S&W76 (below).
SW76 - C&R, factory gun, good history (brief military + PD), good mags - may have to tweak readily available Suomi mags depending on gun). Fun to shoot.
Stemple - versions of the SW76 (including. 45 cal versions).
Reising ‐ C&R, military and PD history. Mags difficult to find today but anticipate that this will change. .45 cal.
Other Mac family guns + probably others that I'm not thinking about right now...
Go shoot some guns and find the flavor that appeals to you. Some guys want the 5.56, while some like the 9mm (more places to shoot, less $$ to feed, suppress better, etc.). Are you a shooter or a collector? Some platforms do better in active shooting competitions. Good luck!
