Car auction any use

I am thinking of buyinga 2005-2006 Almera,Corolla type car, checked out the auctions for similar but the milage seem's mostly to be 100k plus meaning twice the aveage these cars should be, any ideas or just go to main dealer and pay over the odds for a car

I'm was thinking of selling my 05 Corolla, how much are the dealers looking for them. I need to change to diesel as have big commute.