The sign for "trade," "replace" (or even "atonement") is done
by using "F"-handshapes on each hand. Hold one hand forward and one hand
near your body. Then switch the positions of your hands.
Animation: TRADE (version 1)
If you mean "trade" as
in "trade in," "exchange," or "swap" then use this version of the sign.
It is done very quickly. The hands are in "closed-X" handshapes. Hold
one hand in front of the other. Switch places and then switch places again
but do it in one smooth motion (no stopping until the end of the sign). When
you do stop, do it forcefully.
EXCHANGE / swap:
Animation: TRADE (version 2
Also see: CHANGE
You can learn
American Sign Language (ASL) online at American Sign Language University ™
ASL resources by Lifeprint.com © Dr. William Vicars