My Mum is a mangosteen farmer and is willing to sell them to the 'hood at wholesale prices. They are organic, but not certified because that's too expensive on a small farm. The only insecticides used are aeroguard (on the pickers, not the trees) and a trap for a nasty sucking moth (poison is inside the trap and doesn't end up in the soil or on the trees).
The farm is on the edge of the Daintree rainforest and has been well managed for the past 20 years, with an indigenous timber forest planted on the hills and riparian zones, and wetlands restored to create a buffer for excess nutrient run-off (which is no good at all for the reef). Since Mum has been farming it, the creek is visibly healthier, there is thick rainforest canopy and under storey where there used to be weeds, grass and erosion, and the birds, wallabies and dingoes seem happy and abundant.
Mangosteens are the SE Asian cure for everything (from gut and inflammatory issues to schizophrenia) with loads of antioxidants and free radical fighting goodies. If you're keen you can use every part of the fruit. And they are even more delicious than mangoes and lychees.
Cost would be $10 a kilo plus freight, in 10kg boxes. Freight minimum is $50, which will get us about 10 boxes. After that it's about $4.50 a box. At the market they sell for a few dollars each, and are never as good as mum's.
She's at the very end of the harvest, so you'd have to give me you're order by Monday next week. Once I have the orders I can give you the final price.
Email me at firstname.lastname@example.org.