How can I decorate my horrible sitting room on a budget?

I am renting so can’t get rid of anything, I can only work with what I’ve got.

My sofas are a horrible blue and all the other furniture is wooden. The carpet is grey and the walls are cream.

I don’t have a problem with the furniture but I would love if the sofas could somehow match the rest of the room.

But I’m not allowed to get rid of them so not really sure how I can improve them.

Also any tips on what I could put up on the walls other than photographs? That is cheap?