Hey guys, I did get a chance to stop in to Prolite gear in Bozeman a couple weeks ago and took a look at their spinnaker. I talked to a nice guy who just pulled up thier website and saw the "sold by the yard" notation and said it should not have been sold by the foot. However, it certainly isn't their primary item of sale so maybe you contacted one of their employees who wasn't aware that the price should be by the yard?
At any rate, it is a very small company and they seem to only have a few employees. All of them have been helpful with my questions so far and certainly don't seem like the sort of people who would try to trick you, at least I hope not. I made them aware of your complaint that you got it by the foot so hopefully it won't happen again. If you decide not to try ordering from them again, consider giving thru-hiker a try. Many people on this website have had good experience with the guy who runs that website, Ayce. I don't know about overseas shipping though. Good luck with everything.