The answer to the first part is what it means to you. I don't have an emotional attachment to the history of the course so for me I'd pay £100. As a course it doesn't appeal more than that.A simple straw poll
What would you think is the right price to pay to play The Old Course
And what’s the maximum you would pay for a round at the top courses
Second part, probably £150. Now, if you said I can play a particular top course for £155 I'm probably not going to miss for a fiver but but that would be the target, max, figure.
ToC being £270 doesn't stress me, plenty of other courses to play.