Always used Vhit powders and swear by them. There's always good prices out in the gunshops but try getting it shipped. Special courier required due to some daft legislation.
Forget finding a deal from a dealer far away as you'll loose any saving in P&P.
Build a relationship with your local dealer and convince him to give you a good price.
I can do it at £62:50 per kilo when I buy it in 20kg bulk containers and you bring your own tub - although 20kg is only a good weekend's worth of ammunition at the steel plate challenge if you shoot a .300RUM...