The most sought-after Idaho plate is a 1913 passenger plate. That was the first year the state began issuing plates. Those can go for $3,000 or more.
Contrary to what you might think, the 1913 plates are not the rarest Idaho plates. There are about 40 of them in collector’s hands. There is only one Idaho motorcycle plate known to exist for the years 1917, 1920, 1922, 1929, 1934, and 1943.
Smith found one of his rarest plates on eBay for $30 a few years ago. It’s dray plate from 1940. A dray was essentially a beer truck. Smith thinks it might be the only dray plate from the state that still exists.
Even rarer than plates are windshield registration stickers. There are only three non-passenger stickers from 1943 known to exist. Windshields tend to get smashed on old junk cars.
This might be a good time to point out that finding a rare old Idaho plate isn’t like winning the lottery. Most of the collectable plates sell for under $100.