I was wondering about the boosters that are being traded. Can you only get them in game through spending crystals and buying actual physical packs?

That or by winning tournaments as far as I know of.

This. Packs you buy with trainer tokens are locked. If you enter tournaments those packs are tradable though. Against the tos of the game to trade for outside currency technically, but thats how most people here on jsp sell their packs.

Hmm.. I could probably win some tournaments. Thx for the info guys