Heheh... yeah. I've watched a couple rentals on Vudu and agree, the UHD quality is pretty good.I have found the UHD quality of VUDU rentals to be quite good. The app is on the TV. So, if your girlfriend is concerned about the expense, opt to rent, not buy. Then just wait for good sales. That's what I am doing. Well, mostly. Sometimes you gotta splurge.
As for the girlfriend... it's kinda funny. We saw the 55" and 65" side by side and she said "get the 65" and didn't question the price. But now she wants to question movie purchases. LOL
I do pretty good though... generally I pay in the $15-$20 range per movie... some I've gotten for a few dollars less, but I do my best to not go over $20. The exceptions being Coco ($27) and the Planet Earth 2/ Blue Planet 2 sets.
Either way... it's worth it to me for such stunning PQ. I had a friend come over last night and I showed off the TV with some of those LG 4K videos... he was like "Whoa."