Where can I DL/ Buy Japanese Music?

[Sierra G719]

FLOW's Music in particular, I became a fan of their stuff after listening to Go!, Sign, Re:member and Ambience. Please help? Thanks!

 

[Yatori]

just google it.. i think many had upload it since it an old songs

 

[Hanabi legendary Kunoichi]

sometimes youtube helps, have a lot of Vocaloid songs you can get.