unless its really special it will never be an investment, not sure what its costs now but it was over �100 to put on retention or transfer vehicle to vehicle.
I have one for my wife, paid over �500 from DVLC over 12 years ago, the costs over this time has probably doubled the price but i doubt if i would get �250 if i tried to sell now. But its unique and looks good on the car and also makes it difficult to age the vehicle...
oops, got it wrong , its �80 to tranfer or �105 to put on retention,but once on retention its free to transfer to another vehicle..The last time i transfered it was fairly quick remembering that you also need the tax disc changing to the new number, only 4-5 days.
My personal number plate was from the DVLC and it was the cheapest one they had - Just a coincidence it was my initials, year (62) and month (MAY) of birth.
To me they are a fun thing but personally, I would never spend mega bucks on one