What's the cheapest tier point?
I'm about to buy some tickets, but I'm wondering about tier points and how much they are worth to most flyers.
For example,
A WT+ ticket from IAD-LHR is $850-ish, with 150 tier points. That's about $6 per tier point.
An economy ticket from LHR-Berlin is $550, for 40 tier points, or about $14 per tier point.
Has anyone ever come up with a good average price for tier points? I can see paying extra sometimes to get the points, but on other occassions it doesn't make sense.