"...same size as all 308/30-06 brass..." A .225 Win is a semi-rimmed case. Same diameter, but with a different extractor.
The value of any rifle depends on condition and how much you want to pay.
Epp's is listing .225 Win ammo and brass. Doesn't say what make or how much though. I'd bet that Shooter's Choice and Goble's has it too.
Winchester is listing just one factory load. Wholesale Sports wants $31.99 per 20. That appears to be the only factory ammo available.
I have data in an old Hodgdon manual, if you want it. Mind you, there's current data on Hodgdon's site too.