I see no reason why TNG wouldn't be priced similarly to other Blu-Ray TV sets. I paid $50 or so for each of the TOS sets, and I expect the TNG sets to cost about the same.
I purchased Star Trek
on Blu-Ray for the same price, but that was only after the series had been on sale for some time, no? I expect Star Trek: The Next Generation
to have an astronomical SRP and to be actually sold (initially) somewhere in the ballpark of 80-100 bucks. When it sales for $50, then I'll pick it up.