1) Go to walmart or a thrift store and purchase about 10 ft of cheap brown cloth, should run around $10-$20. Depends on how much room you want to have.
3) If you want to make pants wrap it around you and make a cut in the middle up towards the crotch on both sides of the cloth to make legs.
4) Take the cloth and fold it in half so that it's the same width.
5) Either sew, staple, or use safety pins to close up about 3/4 of the length on one of the longer sides and close up the opposite side to the fold. Note that staples and safety pins can easily come undone.
6) Sew or staple your pants if you make them.
7) Cut out cardboard antlers and a nose.
8) Tape/pin the antlers to a strong headband
9) Use string or elastic to tie the nose onto your face. Make cuts to make it more comfortable. The pricier route would be to buy a mask.
10) Cut a thing strip of tail. Wrap and staple any object like cardboard at the end and color it black to allow it to swing. Then attach it to where the butt would be.