What is it with the Royal birthday and thai longans? Every year perhaps thousand of boxes of them are sold, not by one seller, but by almost every other seller in town. And have you ever checked their price? They are sold at BND3 per kg or BND5 per 2 kg, by every vendor! Do they sign an agreement not to sell at different price?
And a tip, they are much cheaper in Bandar than they are in KB. And just don't eat too much of them, or else you will end up having a bad sore throat.