What should I expect to have to replace on a 1999 Honda Accord with 123,000 miles

But has the timing belt ever been changed? If it fails it can cause internal engine damage, You can see that repair price here www.repairpal.com/estimator

Your transmission very soon as to that 98-01 accords have defective trannys

just about everything ,its going to like marrying what you thought was realy nice girl and then finding out she was a hooker with 123000 on the clock ,it will only end in tears !