Seriously what kind?
Native hawaiian shrimp (Atyoides bisulcata) is not legal to sell trade or export from the islands. Plus they are very rare and hard to find.
Non native species such as Neocardina denticulata sinensis which have invaded and taken over the native shrimps' habitiats are not legal to import or export from the islands although you can purchase them in every pet store on the island.
The anchialine pond shrimp (Halocaridina rubra and other Opae 'ula) can be purchased at several online stores. You don't need someone from hawaii to get some. From my experiences however, they cannot live in freshwater despite what others may say.