A link was posted in this thread that sowed the pricings for Yonah. 1.86 was < 300$, 2.0 Ghz was like 400 with something, 2.13 was 650, and <1.86 the price difference was not that much, so it was clearly best in performance/price-wise to get the 1.86 thing.
As for as 2.13~3800+ =>...