First off NEVER skimp on STEERING TIRES!!!
That said, in NO WAY should a tire for a large motorcoach cost $875.00!!
Do some research through a reputable TRUCK TIRE shop locally if you can-I'm thinking more in the range of may be $400-500 for a top rated tire, I'm thinking you priced the $875.00 one at a typical camper repair place where they nearly double the prices comonly found at a truck tire shop.
ALSO if you have one front tire wearing like this then you have an allignment or steering system problem that needs to be corrected.
Here is a Michelin tire I found by Googling:http://simpletire.com/michelin-255-8...FUWQ7Qod70xk7w