The topic right before this one, is "The Trading Post", I would suggest taking a look at some of the other bills that people have posted for sale, and seeing which format you like the best, then just follow their lead. As far as price, you can give a specific price that you want for it, and possiably include that you'll take best offer, if that's an option; or you could give a deadline, and take the highest bid that you get by that deadline (be sure to include date and time, and what time zone since this is a national site).
The most important part is to be as specific as you can be with the condition, mention anything that makes it less than perfect.
hope this helps