Worldrecord, c'mon now!
Cheap ammo? Please!
You just bought a weatherby. Ammo aint cheap for that thing.
noslerammunition.com charges over $100 per box for thier new "custom" ammo.
You might want to try http://www.cpcartridge.com/30378wby.htm
I've never used them, but they seem to offer a large variety of ammo. It's $67.50 for a box of 20 rounds of 200 accubonds. They list velocity a 3300 fps. I'd give them a try for that price. If it works out, you'll save $33 per box. I'd take a shot. (no pun intended)
I don't think weatherby has accubonds in their 30-378 ammo line.
Ammo is the most important part of the investment you just made. Buy crap ammo and you might as well have bought a crap rifle.
You never mentioned how far you plan to shoot this thing?
That would help determine your ammo choice and your scope choice as well.