If stopping echo is your only goal (and you want to keep it cheap), then some thick blankets all around will do the trick. If you want proper sound absorption and a "dead" room, then using a decent-quality studio foam like 2-inch Auralex is ideal for that purpose.
If stopping echo is your only goal (and you want to keep it cheap), then some thick blankets all around will do the trick. If you want proper sound absorption and a "dead" room, then using a decent-quality studio foam like 2-inch Auralex is ideal for that purpose.
Unless you plan on applying a fireproofing fabric to the blankets - I would advise you to avoid that approach - blankets hanging down around your walls is one hell of a fire hazzard - and they go up real fast.
The foams are an effective product - as are rigid fiberglass - 703 or 705.
If you hang rigid fiberglass a few inches off the walls (and below the ceiling) it will help with high frequency reflections as well as tame some of the mid and higher bass frequencies.
I would avoid a completely dead room if I were you - it's very annoying.
Be certain that whatever materials you use are properly fire retardant, including whatever cloths you might use to wrap the fiberglass with should you go that route.