Looking For Basic Attachment Advice

So I unlocked puppetmaster and understand I need attachments from either the npc or Auction house and then I trade them to a NPC. Should I buy all attachments at once and get it out of the way or should I buy only what I think I'll need? I plan to use Pupp for tanking and duo box x2 pupp. THere are so many attachments and some are on the ah but they may also be at a npc shop somewhere also?