What can I put or do to my room to block exterior noise?

Recently I got a remote job, It’s a great opportunity for me but for my disgrace my family loves being annoying and noisy. The house also has a lot of echo and I can hear everything in the first floor even when I’m im the second and far from the stairs.

They know about the sound problem but doesn’t seem to care at all so I know they won’t collaborate.

I want to block as much sound as possible, my room is 3.5mx3m. I was considering in investing USD300 or USD400 in that.