... on the snowmachine forum in response to a cheap sled thread, but decided to post here instead.
A cheap tow sled can be made for about forty dollars which will serve well for ice fishing and light trail duty. Buy one of the heavy duty play sleds which can be purchased at Fred Meyer (don't get a thin one). Also buy the following:
-a stick of 1/2"or 3/4" steel conduit,
-2- 2"x1/2" bolts,
-4 1/2" fender washers,
-4 regular 1/2" washers,
-2 regular 1/2" nuts,
-2 1/2" nyloc nuts,
-2 small clevises or shackles,
-several (4 or 5) washers that fit around the pin of the clevis
Cut the conduit to 4' lengths, then with a hammer gently flatten the ends about 3" up on either end of both pieces. BE SURE TO FLATTEN THEM SO THAT THE ENDS ARE PARALLEL TO EACH OTHER! Drill a 1/2" hole in each end as close to the same as you can manage (about 3/4-1" from the end). Drill a 1/2" hole in the front sides of the sled a little back from the front, and down a little (make sure they are exactly opposite of each other on each side). Put a bolt to attach the conduit lengths through each hole in the following manner: bolt, fender washer, sled thickness, fender washer, regular nut (tighten hard), regular washer, flattened conduit, regular washer, nyloc nut. Tighten the nylocs so as to not cramp the conduit between the washers.
Next gently bend the two conduit lengths toward each other and until the holes in the ends align, then attach 1 clevis to the ends by putting through the pin and enough of the washers so that the clevis doesn't move up and down in the holes. Tighten this clevis pin with a wrench. Take the other clevis and put it through the "U" part of the one hooked to the conduit, then finger tighten the pin. You can use nylon twine to tie the one clevis to the other so they flex but stay hooked together in one place. This clevis is what hooks to your machine's flat hitch.
Now finish your sled by drilling a series of 3/8' holes about 6-8" along the sides and back of the sled, and thread rope along through these holes so you can bungey down your gear.
Voila, you have a sled which (with gentle use) can last you a bunch of seasons of ice fishing.