Help in Making Room Sound Better

Hey guys , I built a band practice room in my garage years ago . I knew nothing about acoustics at the time so the dimensions of the room are really bad . The walls are covered with sound deadening board from Home Depot and has carpet on the floor , so the room is dead , but has tons of low mid , bass build up . I wanna turn it into a home studio to record drums and mix . I know making it more live probably won't work since its so small . I open the door when I record drums and it lets a lot of Bass escape . Always tons of EQ cut in the 300-500 range to get things workable . What could I do to help this room ? Budget is as cheap as possible :D Thanks , Recording drums in this room might be too tough and expensive to pull off , so maybe just keep it a Mix room .

Add basstrapping. There's lot's of info on that on this forum (esp. the "acoustics" part of this forum). Read and learn. Happy hunting!

What TYPE of bass trap would be most effective in my situation ? If I got 703 covered with fabric and put them everywhere , would this help much ?