Some good items would be:

Bad rares
Mech angel helmets
Mech angel wings
Freedom wings.
 Dance and say something like "Trade me hammocks, I accept". Or,  "Plz trade me hammocks!" Anything similar will work., If someone tries to trade you something else, decline. You want hammocks, remember.
Get some items people will trade you for.
Go to Jamaa Township.
Accept all hammock trades.
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