This type of blind costs only a few dollars to make yourself, and can be used when you only need coverage on your front side. Smaller versions can be made to use in the windows of vehicles, or windows of buildings.
Buy a cheap piece(s) of material than can be made into a single piece about 7-feet square. This allows adequate space to both sides, and enough room to stand up fully without being seen. Pick a location where you can string a piece of wire or rope from tree to tree, or from any other objects. Then simply use clothespins to attach the cloth to the wire or rope. In windy conditions you can place rocks, etc. on the bottom of the cloth.
I usually cut a vertical slit intersected by a shorter horizontal slit about 5-6 feet from the bottom. This is for a standing-shooting position. The slit should be large enough so that there is plenty of room to swing your telephoto lens from side to side, and up and down. Since you could be very close to wildlife with excellent vision, I make another smaller piece of material about 1-foot square. I make a bunch of angled cuts just long enough so that the resulting circle will fit snugly around my lens. A vertical slit from the circle to the bottom allows me to slip the material around my lens, then pin the bottom pieces together with a safety pin. This piece of material gets pinned to the blind, leaving lots of slack so that movement of the lens is not inhibited, yet there are no gaps around the lens through which you can be seen.
If you prefer shooting from a seated position, make another opening 3 or 4 feet from ground level.
This blind can just be rolled up and carried in your backpack. With the low cost, you can also leave this blind set up in remote locations and not worry about it being stolen, etc.
Since my blinds are usually set up in forest or bush locations, I usually use dark green or brown material.
#1 - cut-outs for 7'x7' blind
#2 - cut-outs for lens-to-blind cover
#3 - blind strung up between two trees. In this set-up, there would be cover to both sides, behind, and above from tree branches or bushes.
In this set-up, there would be cover to both sides, behind, and above from tree branches or bushes.