Vanuatu’s currency is the vatu (VT), which floats against a basket of currencies including the US dollar, so it is reasonably stable. It’s easy to exchange Australian dollars and most major currencies in main banks.
Commercial banks in Vanuatu are ANZ (http://anz.com/vanuatu), Westpac (http://westpac.vu), the local National Bank of Vanuatu (NBV) and the French bank Bred (www.bred.vu).
In kastom terms, tipping is an obligation that the receiver must return so, to avoid embarrassment, keep your ‘tip’ to a smile of thanks. Restaurant staff in Port Vila are happy to accept a tip, though.