Rockauto to can be awesome with shipping prices sometimes. I have had huge orders like that next day air for under $30. Not sure how they calculate shipping but it seems to always favor the customer.
On the good side of things you still had 90 psi in #7. #6 did have closer to 165-170 and I only think we let the motor spin 2x while testing. I think you should jump on this sooner than later because if the seat falls then you will probably end up needing at least a new head if not a piston also.
Even with the 90 psi and the motor barely twitching, cyl 7 was completely dead. It never came alive the whole time the scanner was hooked up. With this situation and all the raw fuel going into the exhaust that is where your po430 code for catalyst inefficiency comes into play. I would consider unplugging #7 injector if you keep driving it for the time being. It will at least save the cat.