Just to amplify this, common parts across several models and somehow be more expensive for the "luxury" version. Rear hatch gasket for an '96 Oldsmobile Silhouette mini-van was twice what the exact same part for the Chevy Lumina. Only difference in the two vans is a few more gadgets and more acoustic insulation in the Oldsmobile.
You might save on the initial purchase, but there's a lot more stuff to break, and when it does it's really expensive.