Another question for somebody in England (cost of stamps)

[abbet659 at hotmail.com]

No: HPFGUIDX 87580

How much is a stamp, is it the same size as a US stamp?  Just 
wondering how much it would cost to cover an envelope with stamps.  
Seems to me that would cost quite a bit of money for a poor Wizard 
family, so maybe they made their own stamps.  If they can make 
stamps, couldn't they make muggle money, have somebody launder the 
money, then take the real money to Gringotts and exchange it for 
wizard money?

Abbet