I am in the process of selling a lot without a real estate agent. I just put up a couple "For Sale" signs and bought a standard forms package at Staples (other business stores should have similar packages). It includes the standard form that a purchaser might use, as well as a checklist for all the factors that should be taken into consideration.
Luckily, the lot is near a major road, so I am getting a lot of interest without requiring a real estate agent. However, once a formal offer is made, yes, I will use a lawyer and expect a deposit. One aspect in which a real estate agent would be useful is the hassle of showing the houses on the lot. Both houses are rented out, and I find it a real hassle to have to give the tenants 24-hour written notice about a viewing, and then have to return to actually show the potential purchasers the houses.
I am sure an agent would have generated a lot more interest (through access to the MLS service), but I am doing okay for now.
Good luck!
David