[TwoforFun]

She is not a friend if she doesn't understand, plain and simple.
I also think if she can't pay the full amount then she can't afford the vet bills that come with getting a pup. There is no contract between you and the byb so you can just get yourself the pup and have her work out the details with him.
I wouldn't stress the situation, if you need new friends go to church, bars or whatever your preference in socializing. I wouldn't want anyone taking advantage of me.