I’ve been a fan of both Mullvad and ProtonVPN for years. I ultimately went with ProtonVPN since it is included in my Visionary plan anyways. I did like Private Internet Access until they got bought by an adware company.
Anyways, ProtonVPN supports P2P and still has port forwarding. I’ve never had issues with the paid plan, but have heard of problems on the free tier.
You might get something slightly better on the used market. But, if you’re not looking to run anything resource intensive, check for Beelink mini PCs on Amazon. They have some on sale right now that hit your price range.