I think the best entry, for low cost, would be a 500C transitional body. They are the same as a CM, removable viewfinder screen, but still carry the C marking...not the CM marking. If you watch the 500C on ebay a lot of times the seller doesn't know enough about the camera to know it has the later screen feature.
I've got all C series lens and couldn't be happier. You'll hear a lot of talk that parts aren't available for this series, but I've never seen anyone on here talk about having to throw away a lens because parts aren't available. Hasselblad may not have them, but there are a lot of parts in the field and some of the later springs can be replaced with slightly modified newer Hasselblad springs.
This strategy has worked for me, YMMV
I try to buy low and send pieces to David Odess for a CLA to get me off on the right foot.