James is correct, Sold home prices on Trulia do not include any incentives provided by the seller to the buyer or to the buyers agent.
You are correct John in your assessment also. There are many sellers paying a portion if not all of the closing cost on behalf of the borrower.
The best scenario for you and your family should be looked at by your lender. You could be a slightly higher rate for no closing cost with your lender and take a lower price on the home you want to buy also. You need to look at how long you anticipate living in your new home realistically and determine how best to maximize the time you own the home. If paying a slightly higher rate to your lender for a no closing cost option and taking a lower price on the home since the seller is not paying closing cost on your behalf equals less money out of your pockets over the duration you own the home then that might be the better decision. Your lender and Realtor can help you calculate the math.
For instance, lets say it will only cost you $25 more a month for the no closing cost option and you plan on living in the home for 5 years. That 5 years has cost you only $1500.00. In this scenario, you would be better off having the seller reduce the price of the home $5000 versus having them pay $5000 towards your closing cost because in this scenario you would leave $3500 on the table. Make sense?