I recently experimented with linux VPS and server hosting and was really surprised at how well it handled game servers.
If you want a cheap server to use and play with friends then this could be a really inexpensive way to do it.
https://www.ovh.co.uk/vps/vps-ssd.xmlI don't know what the size of an Arma 3 linux server is but for the top ssd @ £11.99 would give you a lot of space and performance for a small game server.
I was using the smallest vps and ran a L4D2 server with 8 players and it used only 15% cpu max.
If you can find out how much the server install actually is then you might get away with option two at £5.99 which is cheap as chips and easy maintenance.
https://gameservermanagers.com/#supportedgames I used this to install my server.
Whatever you do just don't use expensive hosts for dedicated server. Even OVH do a dedicated one for for £49.99 and offer good ddos protection and plenty of space.