Shopping is very limited (especially in Vava´u) and reduced to the absolutely necessary items. If you stay her for a few weeks you should bring along some items/equipment that can be very useful:

Bring along...

IMPORTANT:
  to treat minor cuts we suggest to use powdered penicillin-tablets to apply on the wound instead of any antibiotic-creme. Wounds must be kept dry and covered, applying cremes may start the wound to fester.

  swiss army knife
  torch / flashlight
  first aid kid (medium size)
  strong sandals (caterpillar or jack wolfskin)
  light bermudas (not hot pants)
  light shirts
  warm sweater for cool nights
  raincoat
  snorkel gear
  swimming suit
  razor blades/cosmetic cremes and utilities
  spare batteries
  sunglasses
  (spare glasses for reading)
  all your medication (pills, cremes...)
  (small hair-dryer)
  adapter or transformer
  beach- / plastic shoes

 
Your dress should be loose and comfortable.
  When the wind stops and it is very humid you may
  get a heat stroke, if you dress up too "hip".
  It makes sense bringing along a straw hat or a
  baseballcap, the sun here is very strong and a sun
  stroke is no fun when the doctor is far away.

 The tongan soil is dark reddish-brown and colours
 your clothes like tea. Have clothes that survive a heavy wash!

  If you intend to stay longer do not bring along leather.
  If the climate is very humid leather will mould
  within days. Cotton and the new light fabrics are ideal.
  Any metal (zippers etc.) rusts very fast. Cameras may develop condensation inside (use the small
  hair-dryer!).
Some Non-Tongans have developed a strong allergy
  against the bread from tongan bakeries. If you feel
  sick after you return home, be tested for a
  yeast-fungus. Those with allergies are adviced to
  eat the european-baked bread from the
  Lighthouse-Café.

  Headlice are not rare. Take along a lice-shampoo.

  Condomes can only be bought in the hospital. They may be stored for years without cooling. Bring along.

  We have no dangerous land-animals, no snakes or poisenes animals. The big centipede ("molokau")

is feared, his bite is very painful and may result in temporary paralysation of the bitten bodypart; his size ranges from that of a matchstick up to a
  small snake. He loves to hide in dark an wet places.
  If you like to take bushwalks: no sandals!
  Bees and wasps are usually harmless, some
  spiders are quite big but not dangerous. If you tend to be allergic, take along appropr. medication.

For all sea animals/fish etc please consult your
  bookshop.

  There is no Malaria in Tonga.

  Have a vaccination against Hepatitis and Tetanus. Seek advice for typhoid prevention.

Dengue-fever may occur.

Pets
If you intend to bring along your pet be adviced that Tonga has a very strict quarantine. The islands are free of rabies and deadly dog-, cat,- cow-. and horse-diseases or epidemics.

The Vava'u Pharmacy offers a range of medication and cosmetics, but due to the smallness of our Island the stock is limited!