I may be in financial trouble!
As for maintenance, all I have done really was replaced the headlight housings corner lenses and grille but that was only to have a fresh clean look in the front. Other than that, an alternator, oil change with 5W-30 Mobile 1 Fully Synthetic, Motorcraft oil filter, new plugs, new front OEM air shocks and that's about it that I can think of. From now on, it should just be oil changes, plug changes, just the normal things. All the high dollar parts I put on should be good for the rest of the life of the car but the day is coming when a lot of the new stuff will be gone. Another reason why I got it when I did.
2K for car.
$320 for the grille, new
$480 for housings, new
$300 for corner lenses, new
$378 for front right air shock, new and should be good for 10+ years
$370 for front left air shock, new, same
$170 for reman alternator, lifetime warranty
$75 invested in dual HID's with slim ballasts and a relay kit
$380 for tires with rated for 70K BF Goodrich T/A Pro Touring
$300 for some Octostars that aren't on it yet but will be this week
$25 for all SMD LED 6000K interior lighting
$115 for 850/1000 battery
All prices were to the door, unless I bought locally.
I'm sure there is more but the majority of the things above is only optional. I will never sell the car and it is garage kept and not daily driven.
All depends on how long you want to keep it and if you want to take care of what you have. Mine is a southern car and completely rust free and 99.9% of the time, it never see's rain.