Sally is correct, Trulia does not accept FSBO listings. There are sites that do, but if you posted here and on every other site that allows you to, you won't get the level of exposure that listing with a great local agent and appearing on your local MLS will get you.
A great agent is worth more than their commission, but a bad one or none at all can cost you way more than just a commission. Consider discussing your options with someone worth working with and then do whatever you feel is in your best interest. Best of luck however you proceed.