Well I bought my 240z 16.5 years ago and decided I should see what it has cost me. I used it as a daily driver for the first 6 years and a summer/fun driver for the last 10. I added up all my receipts and the total came to $14,544.65
$1000.00 of that is the original purchase price back in 1998.
$5614.58 went to general maintenance. This includes a partial engine rebuild, head gasket, a couple of starters (seem to have bad luck with those), and one alternator. It also includes a lot of trouble shooting various problems and minor maintenance items.
$4425.07 went to body work. That includes $1600.00 in accident repairs (I HATE the 405). and $2700.00 for an amateur paint job that will need to be redone when I get the funds.
$3505.00 went towards upgrades. Those include a Mallory distributor, new carbs from Z therapy, new wheels, new front bumpers, weather stripping, new seat foams, new leather upholstery, and some new badges.
All in all it works out to about $73 dollars per month which is a pretty good bang for the buck. Especially when you factor the value of smiling every time you drive:)