The Frag Farmer's Market is a giant sized coral market. Imagine 60 different people setting up tanks full of corals for sale. Sellers include the big names (Jason Fox, Pacific East, Aznutty) all the way down to some small scale hobbyists who grow out at home. The buy in for shops and hobbyists is low, so they pass their savings along to you. You will not find a bigger selection of corals, or better prices anywhere. You can look at it this way, you would probably drive an hour to a good shop to buy, what if you could drive 2 (depending where on the Cape you are) to see 60 shops all in one place? I have been to quite a few swaps, and shows and I think that there are more corals at the FFM than any other one I have been to. You name the coral you were hoping to find, it is there, and likely in a few different people's tanks! This is the biggest one in the area, easily. The local CT guys call it "Reefer's Christmas." The only thing that I always hear complaints about is that it is overwhelming when you first get there.
Add to that a raffle with all kinds of stuff that you would want, including corals, a ton of high end clownfish, gift certificates, pumps, lighting, supplements, frag tanks, an Apex controller...
I am working on putting together a few talks during the day, on photography, general reefkeeping, etc... I'll post that info as I get the details ironed out.
I run the FFM, so I may be biased, but for $5 admission, you won't find a better place to shop for frags and get a chance to chat with a TON of other reefers.