Fair price for an 88 v20

I bought an '86 StepV last year with a 1987 Johnson 225 with a trailer and paid $4,900. The boat needed some work but overall it's been a great deal. I "grew up" with a 1974 StepV (165 OMC I/O) so I knew the model well and spent the better part of a year shopping for it. Last year we needed to replace the gas hose and the vent hose because of dry rot. The outboard needed a new starter and fuel pump but has been reliable at least for the first year. Your biggest expenes may be engine related.
Good luck. You will love the model.