Did mining + BS at the same time. Did 1-375 is 5 days.
Spend ~200g 1-350 because I got impatient with a few skillups.
T1 costed ~500g since you get all the earths from mining, just need however many Primal fires you didnt get from mining.
350-375 costed roughly 700g, because I bought A LOT of Eternium for 360-375. Once again, spent the money only because I was impatient.
T2 costed me nothing of course. Luckily already had the Nethers banked, but not like those cost anything more than time.
T3 costs nothing unless you can't be in a SSC/TK guild. I still don't have mine, but not to impatient as T2 is plenty fine.
Summary of BS, if you are patient, and take your time, BS can cost you nothing more than the cost of learning Plans as long as you have mining.
As for the haste proc. It is amazing. It proc's VERY often, usually a minimun of once per 2v2, sometimes twice. Anywhere from 2-4 times in a 5v5.
In PVE usually once per trash mob.
Oh, and haste isn't getting a confirmed nerf. Blue's were unaware of the change, and are "looking into the haste change".
http://forums.worldofwarcraft.com/thread.html?topicId=1134196633&sid=1