In MO, it's $25 for as long as you own the vehicle, for a historic plate. Historic plates are limited to 1000 miles of here and there driving, but if you are driving to a car show, swap meet, the parts store, and so on, those miles don't count toward the 1000, and I've heard from others that if they do get pulled over, they hardly ever have to show them the mileage chart. No inspections, just pick up some cheap auto insurance, get historic paltes, and you're good to go.
And it probably wouldn't hurt to keep a O'Reilly's Auto Parts bag, or your favorite chain, with a new bottle of oil, and then just say that you just picked up a new bottle from the parts store, and didn't need the receipt.
