You do know Vocaloid isn't a single program, right? It's a program, and lots of companies have different Vocaloids.
What kind are you looking for? From the Vocaloid official website, I found a distributor called Zero-G Limited that sells three voice packs, Leon, Lola, and Miriam. You can find it here:
They're 80 bucks per download and 130 for a physical copy (probably much more if you want it shipped to the US, since they're a UK based company).
If you're looking for the Japanese character packs (I'm assuming you are, like you probably want Miku and Rin and all that), you pretty much have two options: one, learn Japanese and find a Japanese software website that accepts American credit cards and ships the the US. Two, search torrent sites. Those are really your only two options for those.