I haven't even seen any Reiwa coins for sale yet. Most likely they will strike millions of them and the temporary insanity for them will drive prices way up. A few years from now some new insanity will strike and their prices will likely go down again to more reasonable levels. I would wait until that moment to buy them. Remember the 1999 US Silver set. In the meantime, you could research the prices of Japanese 1989 proof sets, when the Showa era ended and Heisei era began. There could be interesting, possibly relevant, information there.
