Depends on the amount of work you can put in, and how much you are allowed to t with your walls by your parents. Soundproofing walls really depends on eliminating pockets of air with insulation. Open space will reflect sound and conduct it through walls easily, with less space, there will be less sound, imagine filling a guitar with insulation. This video gives a pretty good example: https://www.youtube.com/watch?v=GLjhrXFo0Kw
As for cheaper quick ways to soundproof a room, there are certain mats and soundabsorbants you can place on the walls, but it generally isnt as effective.
In all honesty, seeing the quality of refs being this poor, I dread some games. We are going to have to suffer with Simon Hooper at some point, too. We can laugh now, but fucking hell we will all embody Haaland the second Hooper drops another stinker.