How much should a decent set Of rims cost?

I bought a second set of rims from the Subaru-affiliated tire shop when we bought the forester at the end of 2012. there is apparently an oxidation problem with the rims that they have tried to resolve several times but always results in a slow leak. so they said we need new rims. same as the old ones, $400 installed no labor, normally $600.
one issue with the rims has been the apparent coating that adds the color and i don't know what else, has been peeling for some for some time. the tech said he hadn't seen it before but it had to be some de-icer or something, which i thought was odd. i believe these are low end but is 8 years a typical lifetime? i'm not really hot on buying the same rims that have given me grief.

i have to tell them in the next 30 minutes to get my car back today, which i desperately need.