IMO it's an interesting domain but I suspect people are more prone to typing B2B
It's a typical case where having the two would help avoid traffic leak. Anyway the name would fit for a business portal/directory. At present I think you are looking for max low $$$.
I agree , its b2b not btob . if it was b2b then maybe xxx but i would say reg fee unless it gets traffic. if it gets traffic let us know and we can move apprasials up a bit.