Well, if your going in chronilogical order it goes:
First generation vocaloids (MEIKO, KAITO, ...etc)
Second generation vocaloids (Miku, Rin, Len, Luka...etc)
Utauloids or UTAU's (Teto, Neru, ...etc)
there is a game based on vocaloids, but originally its a program.
Probably utauloids
No. VOCALOIDs are not couples. VOCALOIDs do not have to deal with anime or couples. It's only a singing program.
There are a lot of VOCALOIDs. VOCALOIDs are now up to at least 45, and their are more than 60 voicebanks.
yes
There is no any other VOCALOIDs. All vocals found in VOCALOID wikia are the original VOCALOIDs made buy actual music/recording companies. Haku Yowane, Akita Neru, and Hatsune Mikuo etc. are fanmade based of the VOCALOIDs voicebanks.
around $200
Every VOCALOIDs have diffrent prices. The cheapest VOCALOID is currently $40 dollars and the highest price is about $400. You can buy the VOCALOIDs in their company's website.
To me i think Vocaloids did
depends on which one you buy. Luka is bilingual and can sing very well in english., and all the vocaloids can sing in english, but you can barley understand them.
I'm not sure if this is entirely true, but I believe that after the commercial failure of KAITO Crypton tried a female Vocaloid character (in this case, Miku Hatsune) and she took the world by storm. Therefore, in order to keep on top, Crypton continued making female Vocaloids, adding some males to keep the balance.
In alphabetical order with released Vocaloids so far with some upcoming confirmed Vocaloids. English Vocaloids: Big Al Leon Lola Miriam Oliver Prima SONIKA Sweet Ann Tonio Japanese Vocaloids: VY1 "Mizki" VY2 "Yuuma" Akikoroid-chan Aoki Lapis CUL Gakupo GUMI Hatsune Miku Hibiki Lui Hiyama Kiyoteru IA Kaai Yuki Kagamine Rin Kagamine Len KAITO Lily Megurine Luka MEIKO Mew Miki (SF-A2 Miki) Nekomura Iroha Ring Suzune Ryuuto Tone Rion Utatane Pico Weatherloid Yuzuki Yukari Chinese Vocaloids: "Yayin Gongyu" - probably will not be the official name Spanish Vocaloids: Bruno Clara Korean Vocaloids: SeeU English Vocaloids: Leon, Lola, Miriam, Prima, Sweet Ann, Sonika, Big AL Japanese Vocaloids: MEIKO, KAITO, Hatsune Miku, Kagamine Rin, Kagamine Len, Megurine Luka, Kamui Gakupo, Megpoid Gumi, SF-A2 Miki, Kaai Yuki, Hiyama Kiyoteru.