If they made what E-bay have accepted as a genuine error then provided they refund your pennies in full, then yes they can do this. I think it's to allow for genuine typos etc so someone could show the buy it now price at £1.00 when they meant to put £10.00 and just didn't notice the error, that sort of thing.

I had to do it once a long time ago too - the person had a buy it now of 10p and they meant it to be £1.00......... but the Seller also e-mailed me to apologise for their mistake and the mix up.

C xx