If you use seller manager pro on the other site you have access to sending out lots of automated after auction emails, "you have won" - "invoices" - "item has shipped" - "Thanks for payment" etc.
Why not customise these to let your customers know that you list over here on ebid and can offer better prices because the listings are free and because of the high fees charged over there.?
I set mine up a couple of days ago.
Give it a try.
Dan