Thanks for getting back to us!
Our new pricing and licensing policy was announced on November, 11th 2010. Thereafter we provided 2 months grace period (until January, 13th 2010) for our clients to take advantage of our old pricing and get Sitefinity 3.7 (upgradable for free to Sitefinity 4.0 Standard Edition) at $899, even though the 4.0 Standard Edition alone costs $1999. We are at the opinion that this was a fair time frame for our customers. Please also note that the 3.7 version is officially no longer for sale. We still make exceptions though, as you have correctly observed, and provide them with 3.7 licenses at the price of Sitefinity 4.0 Standard Edition (they will have both 3.7 and 4.0 Standard Edition license).
the Telerik team