Where or how can you purchase B-grade throws?

I’ve been reading alot about B-grades lately, but I don’t have any clue where you can buy them.

most other sites

i heard they sold them at contest.

Yep. As the other people said some other sites, but mostly at contests.

You can usually get them at consistent events and contests. Sometimes the yoyo manufacturer’s website sells them. Trades or even direct from people in clubs/ your friends who “know someone”.