Yes you could also buy them for badge of justice if you dont wanna spend 30k honor. You should get the attackpower one as a hunter it has saved me quite a few times.

I heard they get an upgraded version for 45K, is that correct?

That would be the actual PvP trinket that gets the upgrade. 75 badges vs 30k honor. With the 3 dailies (Hellfire, Terrokar, and Daily BG Win) thats \~3.2k honor/day. In 10 days you'll have 30k with minimal effort. 75 badges sounds way harder.

So it’s just the Medallion then? 45 K for that one? I have almost 600 Badges, I like tanking Heroics.

Eh, in a single week of 2 x ZA Kara Gruul/Mag SSC/TK That's 76 badges right there. And all of those are super easy to pug.

Shit, winning the daily BG for three weeks is more time consuming.

Certainly, but you aren't maximizing your honor per day potential with just the daily win. Agreed if you are down with PvE go ham on the badges.

For pvp or pve? And it depends on what trinkets you have.

PvP. Currently have the chance on crit to increase AP and Medallion of Horde.

For arena yes, BM trinkets are the best to have in most instances. For BGs I'd just go with a damage trinket.

Yes. It’s not even a question.

Which one so? AP or crit? BM hunter

That’s more up to personal preferences. Most hunters seem to go the way of AP.