anytime you can be "out the door" for 500 or less and have a fully functional hot tub I would say you did good. That jet plug was funny, I hadnt seen that before. If you need a new jet housing thermospa doesnt use a sprayed in foam, it wouldnt be hard to fix.
But yeah if the cover is heavy you should consider making that the next investment. I dont recommend buying one online, find a good local dealer who has a good reputation. They probably dont buy garbage covers because they want to help their customers.