PNG daily budget

Hello hi,
I really want to visit PNG next year in February. I'll have 12 days. My initial research has shown that almost everyone talks of how expensive it is. Just how much are we talking about here? Would $US 100 a day be enough (excluding flights)?

I would probably focus my stay to New Ireland and New Britain. I don't dive, but snorkeling is on top of the list ( where is good for snorkeling. Went to the Banda Islands in Indo last year...so I'm spoiled). I'm also not that picky about accommodation.

I'm also really interested in photographing some tribe, but New Ireland/Britain isn't quite the place for that, right?

Any insight much appreciated.
Thanks

Your budget should definitely be enough.

These islands may no longer be "primitive", but if you happen upon a local festival (I did) you could still get some very exotic photos of people in traditional dress and the like.