Try a search engine "Queen Tickets Cardiff" or something similar and see what comes up? Tickets on Ebay will go to the highest bidder and if I was a seller, I'd want the best price available.
Donating some of the "cash" to charity is commendable but I would'nt believe it if I were you. They're only in it to make money.....not too many people are charitable these days.
Anyway, hope you get a ticket. Good luck.
We all of us deeply apologise for this god forsaken shit heap of a building...but we will make it rock.
Brian May Wembley Pavilion 11.05.05.