You can fit a universal type one for under $200 off ebay. Or find the Sea Doo dealer JM Camper online. They are in Maine and are the largest volume dealer. They have the lowest price on OEM Bimini's.
It is really hard to find them used. Most people wanna keep them. For OEM, JM is the cheapest. I had a cheap universal fit one from ebay that i liked but it wouldnt fit under the cover. So i bit the bullet and ordered the OEM one from JM. It is top notch and very high quality. They actually order them after you place the order and it ships from the manufacturer in canada.