Quickest way is to grab his LBE/LBV and drag.
Works good for short distances but as I can attest to you can end up with your pants around your ankles and an a$$ full of rocks and sand. It's better than an extra hole in you though.
Next would be rolling the victim onto a poncho which allows you to drag and carry your man. Add some webbing to the poncho's gromets and you have nice carry handles which won't dig into your hand like 550 cord handles will. Add some branches for poles if you get a chance.
The gov makes a nice lightweight nylon litter especially made for this reinforced with webbing but the poncho is multi purpose.
The poncho litter allows two people to carry a person over rocks, trees instead of dragging and thumping them over.
Left out the firemans carry since unless you are the biggest guy carrying the smallest it probably won't work. Remember you will be wearing gear and so will he. Unless you both strip down to 1st and 2nd line and someone else humps your ruck. If your going through the woods with an extra 200 lbs on your back and step wrong...
Someone also has to grab the injured person's weapon to not leave it behind.
Brigade sells a litter for $65 FRNs like this but you could make it yourself for $20. You just need a poncho and some webbing.
You can also buy a tow line which attaches to your gear and has 550 cord to pull you out of danger.
For $47 you get basically a battle dressing carrier, 30' of 550, a locking link and a carbiner.
Most patriots probably have all this lying around the house. Cost would be free.
You can also toss the metal to make it lighter. Put a bowline at one end of the 550 cord
and put the running end around your LBE and through the loop. Make a bowline at the other end to drag with
and fold and sew some webbing over 6" of it to make it easier on your hand. All this
will fit in a $2 FRN compass pouch and weighs less than half of the Brigade one.