Seco/Niagara rep here... If you can send me a picture of the label on the utters container, I can do some homework for you. I'm not really surprised at the price though. A 3/4" diameter carbide endmill with 3" reach is a pretty big carbide blank, and everyone knows how dis-proportionately expensive carbide gets, as you continue to increase the diameter. I'm thinking the reduced-neck might also make this a special as well.
If you don't mind altering your dimensions & cutting parameters some, we have some nice replaceable-tip tools that might work well for you guys. For instance, in our Minimaster-Plus range, we have a 5/8" diameter, X 3/4" LOC, 4, 6, & 8-flute version. Those would do nice for your high-speed toolpaths. It will be a little less expensive, but not by a whole lot.
We also have a 3/4" X 1" LOC indexable "helical" style endmill, using our 6mm Turbomill inserts. 3 flutes, 15 inserts. (EDP# 25839) These inserts/screws are tiny though, and I still don't know if you'd get as smooth of cutting action as a carbide endmill.
I'd be happy to look into your current cutter, or provide more info for you if you'd like. If you'd rather get in touch with yourSeco/Niagara rep for your area of TN, let me know and I can pass on to you - we have some great folks covering Tennessee.