Here are several entries from a swap we held right here on FAOL.

http://pg.photos.yahoo.com/ph/ghileman@ ... /my_photos

IMO, none of them are too difficult to tie. The custom crawfish was my entry is my favorite. It takes bead chain, chenille, hackle, swiss straw, gold or copper wire, lead wire, rubber legs, and zonker or pine squirrel strips. You could probably substitute cut strips of brown plastic grocery bags for the swiss straw. Not much there that is too exotic. The zonkers would probably be the most expensive. If you want a recipe or step by step with some pictures, email me and I'll get something to you. I'd also suggest tying it reversed on the hook so that the point rides up instead of down. It can be tied in any color you want.
If one of the other patterns is what you are after, each pic has the tyer's name on it. The original swap thread has been lost during the update, and original postings and recipes are no longer available, so you should probably contact each user for the pattern or recipe. All of the patterns were pretty good ones, IMO.
The crawbaby was my other entry and would be the easiest. It is a stripped down version of the custom crawfish. You only need eyes, body material (either dubbing or chenille), rubber legs, and something for shell material (swiss straw, plastic bag, etc.). You can rib the shell with thread or even add some wire for that. That is as simple as you get.