For all sale properties on Trulia, you can click on the Comparables tab, as I've done for the property shown at the link below. You'll then be shown a map and a breakdown of the homes that we've found on the site (both for sale and sold) that are similar to the property you are viewing.
A similar home on Trulia is defined as a close match to the home you're looking at based on property type, number of bedrooms and bathrooms, property age, and of course how close it is.
I hope this helps you. Please let us know if you have any other questions.
I will let someone from Trulia to answer the how to search on this site question. I want to point out two things.
1. Often when question of comps comes up the first presumption is that you are looking to sell and want to get an idea as to what you can sell for. it may be the right one In this case. I would suggest to simply look at active listings for sale and see what your neighbors are looking to sell for. Competing comps are more important to determine a selling price than those already sold.
2. If you are looking to refinance, ,modify, shortsell or include a price into an estate planning, you need what's called a desktop appraisal, which is performed by certified appraisal companies. If you apply for a loan you are going to pay for an appraisal in conjunction if you order it independently you will pay the appraiser directly.