how do you determain the if its a good deal or not?

I'd look at Accords of similar style and condition on sites such as this, and other listings of local classified ads. From there, a good baseline for can be established for a fair asking price. Also, I would immediately pass on any car that does not have complete maintenance records; there are enough used Accords out there to be picky. No reason to purchase someone else's deferred repairs.