Hi Marly 91, I've been to all the places you mention and I run a few thoughts to you.
You need to be comfortable about surfing coral reefs as there is only few spots in any of your destinations that are sandy beach breaks.
I don't know about the flight cost to any of them but they are within your range PNG may be a little dearer because of changing flights at Brisbane>
So PNG , surfing is confined to a number of resorts at Vanimo
on the mainland, Kavieng, Rubio
and several others on New Ireland, and is controlled by the New Guinea surfing association( that may not be its name) which is ensuring that the locals get a share of the incoming money.
You cannot surf easily outside the resorts and their prices can be checked at World Surfaris, Atoll Travel, and Surf Travel Company
as your best bets. They will also have a list of the waves each resort has access to and the ability level you need to handle it.
November to April is the best time to consider any of the PNG resorts.
I would suggest that women going to PNG is OK outside of Moresby and larger towns is moderately safe , there was a rape at Vanimo
several years back and cautionary thoughts would be advisable dress modestly and do not go wandering unaccompanied, if the resort offers a tour of a village or town that is the safe way to go. Discuss your concerns with the tour operator before you buy!Kavieng has the easiest surf = Nusa Island retreat!
Tonga once again coral reefs, check the three companies I mentioned for out of OZ stuff, , there are a couple of waves in small passes out in front directly on the beach at HaaTafu
resort and they can be lefts or rights depending on the swell season, the resort has boat trips to other stronger reef break passes but charges for the boat trip each time.
Corners, Motels and a couple of the others are on the beach. I found Tonga a little inconsistent for swell!
Samoa, some gentle breaks but more prone to powerful swell, two islands to choose from resorts on each, and they need the tourist to help recover from their Tsunami, again check out the travel companies, ring and talk to them re costs and suitability of breaks.
Check out Vanuatu too, a little more inconsistent but may well be in your price range at a budget motel out toward Breakas Resort and Pango Point
, Breakas is a little too pricey for your budget but has a good if occasional left hander right in front. Very shallow and live reef but several breaks in the same stretch, do not underestimate this stretch.Make sure you have good travel insurance that covers surfing and evacuation to Australia, any reputable resort will not take you if you do not have it!
Hope that gives you some idea
I've taken up troll hunting just for fun, instead of a rifle I'll just use a pun!