Get out of town and you'll see plenty of bush knives (machetes) in Vanuatu. Even little kids have them. For cutting coconuts, clearing tracks and gardens, scratching the ground, hunting, vandalizing trees etc., the bush knife is a multi-purpose tool.
Bush knives make excellent gifts for villagers on the islands. You could also buy one and take it home. A bush knife can be used for rough gardening, playing Rambo and scaring your neighbours. I brought two into Brisbane Airport, Australia, and wasn't challenged. The bush knife is an agricultural tool and like most other gardening implements only deadly if employed as a weapon.
There are basically two popular styles of bush knife in Vanuatu: the long and thin, sword-like Sabatier and the broad, machete-style Tramontina. The Brazilian Tramontinas are growing in popularity because they're cheap and rugged. The French Sabatier knives have a thicker blade, harder steel and they hold an edge for a longer time but are said to be more brittle.
Bush knifes come in many sizes. A long blade is better, it will save your hands when cutting brush and carries more momentum for cutting wood and dry coconuts. A 20 inch Tramontina is a good size and weighs about 500g. The 18 inch blade is also nice. The 22 inch feels quite massive. Go to a trade store and try out the different bush knives. The right size depends on your your build, weight and strength. When swinging a bush knife of the right size you should feel the momentum but not the weight. The knife should not pull your hand down.
A bush knive is used much like a hammer: swing it smoothly and let the blade do the work. The "sweet-spot" is about 3/4 along the length of the blade. ALWAYS swing the blade away from you (need I say?). Strike saplings at about 30 to 45 degrees in a downward motion and they will cut easily, at 90 degrees often they just bend. Keep your blade sharp, a flat file does the job quickly.
When shopping for a bush-knife, check several stores to find the best selection and price. Buy an original, not Chinese, no-name, junk. A 20 inch Tramontina costs about 650 Vatu (less than $A10) in Santo. Sometimes the hardware stores are cheaper.
Try not to cut yourself! Don't thrash about with a bush knife, each blow should be carefully aimed and measured.