The handful of small pension-style hotels on these islands are mostly in our US$50-100 price range. Reserve in advance if you need an airport transfer. About the only alternative is to camp in the interior; the Uvéans are hospitable, and a request for permission to camp sometimes leads to an invitation to stay in their homes. Alofitai Beach on Alofi would be a nice place to camp.
Several of the five hotels accept credit cards, but elsewhere they're seldom used. The bank in Mata-Utu gives cash advances but they deduct a high commission when changing traveler's checks. If you'll be visiting Tahiti or New Caledonia before going to Wallis and Futuna, buy your Pacific francs there, as exactly the same currency is used in all three French territories. Euros in cash are fairly easy to change. Though expensive, Wallis and Futuna has the lowest inflation rate in the South Pacific.
This being a French colony, many offices open only on weekdays 0730-1130 and 1400-1630. If you are planning on doing any shopping during the midday siesta, verify the opening hours beforehand.
The time in Wallis and Futuna is GMT plus 12 hours. Though the territory is actually east of the 180th meridian, in 1926 the international date line was moved east, so Wallis and Futuna could share New Caledonia's day. Thus it's the same day here as in Nouméa or Nadi, but one day later than in Papeete.