if you want a dope sounding vocal booth thats still hella cheap, do something similar to hellfires old one, although i wouldent put it in a corner.
build a box, maybe 5 by 4 or something out of pvc pipe, then hang packing blankets/duvets/comforters on all the corners and drape some over the top, the heavier the blankets the better the sound youll get.
the reason you dont want it in the corner is because you have a higher chance of getting a wash of reflections coming back into the mic after they bounce off that wall.
so if you put it in the middle of the room, it still gives your sound waves air to "breath" while not having to worry so much about them bouncing back at you and making your recordings sound like shit.
the heavier the blankets the better, in theory you can do this and it will kill all the flutter echo in your room, and youll have a nice vocal sound, ive been meaning to make one of these for a couple years, it would probably work best if you had a few acoustic absorbtion panels on the walls of your room though.
i also had a booth in a closet at one point, i used hideaway couch matress on one side, lots of clothes behind me, 2 couch cusions also and i deadened every other wall with pillows and blankets. it was a sliding glass closet like the other dude posted, but mine was tiny, like 2.5 feet by 9 or 10 feet.
i found later that if i opened one of the doors and hung 2 or 3 layers of blankets i got alot better sound than i did when the door was closed and i was boxed in there, because of the same principal stated above.
check these out
http://www.acoustimac.com/acoustic-insu ... el-frames/if you cant build your own frames, they sell them here for 10 to 13 dollars.
if your thinking about using insulation, use rigid fiberglass. roxoul or oc 703 or oc 705. you can get 6 sheets for about 60 bucks. they also sell it on that site, i dont kno about shipping to canada though.