What would a good game to buy?

I have been looking at a couple of games to buy. I have around £20. It would be better if it would have like a free mode. Probably not games like 'Shadows of the damned' . Yeah so this is my first post on this website , so reply back :)

So do you like a sandbox game like GTA and red dead redemption?

What genre do you prefer, FPS RPG RTS and so on?