I'm not such a domain expert, but I know that 3 letter .com domains are really valuable. I would advise you to go to namebio.com and search for 3 letter .com domains sales and that shall help you to get an idea.
I dont think you will have any trouble selling it for $60. I would hold out for atleast $300, probably even more. Hold on to it for 5 years and who knows what it will be worth by then.