There are many materials that can be had at the local home centers that are pretty good soundproofers if you can't afford the high powered materials that are on the market today.
One good soundproofer is "rolled roofing" it can easily be had at the local Home Depot or Lowe's. If you staple up the roofing to existing drywall and caulk all of the seams and around the perimeter, you could then layer over that with a layer of 5/8" fire code drywall, and your home free!
The roofing doesn't have the horsepower of lead sheeting or Mass Loaded Vinyl (MLV), but if you're on a budget, it is a good way to soundproof a wall, floor, or ceiling.
If you need more sound advice go to: www.soundproofing.org These folks have tons of ideas and can answer any of your soundproofing questions.

Soundproof Bob.

soundstop