Generally speaking, if there's no real estate fee involved, your cost of selling will include NYS transfer tax ($4.00 per thousand of sale price) , about $400.00 in title closing fees to handle your mortgage payoff, and your attorney's fee, which varies but is generally around $1,500.00
At the closing table, your son and daughter in law will have to reimburse you for any portion of real estate taxes you paid in advance through your mortgage payments.
Overall, if the base sale price is going to be $325,000, you should set the price at about $330k to make sure all bases are covered.
Hope this helps and good luck with the sale!
I sold one of my properties to my daughter and son-in-law, so I have been in your shoes. This is what I am suggesting. I would be happy to come out and do a market analysis for you with or without your son/daughter-in-law present (better if they are there) so you can have a real understanding of the current value of your house.
I may also be able to suggest to you some creativeness we employed when selling to our daughter.
There is no charge for this and no obligations. Real Estate is a service industry and I am happy to provide this service to you.