lol!!
I'm in the same boat mate. My practice room is our spare room at home. it has high ceilings, flat, square walls and is conducive to that swirly, echoy, resonant sound that you most likely have. I just hang some foam and a few blankets to deaden the room. Anymore of a professional approach to 'sound treating' the room would incur the wrath of Mrs Pocket....not advisable!!
As for the neighbours.....I have a young fella on one side who plays drums, guitar and I even heard a trumpet being played yesterday and the other side is another drummer and bass player.....what are the odds?!?!