Not so much selling at crazy prices.... But what is also getting very hard to get, is personalised plates with just the two initials of your first and last name followed by a nice 3 number combination.
All the goods ones are taken, especially in Victoria.
The personalised plates I have on my car, are ones I got 22 years ago, which I've transferred and put on the many cars I've owned and sold in that time.
However, if I was in the market today, that nice combo would not be available.
My suggestion to anyone thinking about getting personalised plates is to buy them now if available from VicRoads or the road authority in your state that issues them. ... If you see a nice combo, it may be gone in a few more months.
Another example is if you want a nice plate for say a Mustang.
All the nice combos containing "STANG" or "PONY" are already taken, especially in states like Vic where you are limited to a combination of just 6 alphanumeric digits, unlike WA where dream number plates are much easier to get with a zillion digits allowed.