Even if you're just looking to get fish and supplies, it makes sense to attend the whole event:
The Group Buys with The Wet Spot, Dave's Rare Fish, Kensfish and Bob's Rare Plants were only open to registered attendees. The free/reduced shipping and or the promotional discount on a decent order could pay for registration alone!
The vendors who sell on Friday and Saturday tend to sell some of their best stuff before the Marketplace. We were lucky to have Frank's Aquarium down from New York on Friday and Saturday (lots of cool and rare cats, tetras and other oddballs)...He was supposed to be in the Marketplace on Sunday but chose to head home on Sun AM to miss the bad weather.
There were some amazing deals on truly awesome fish in the Saturday Night Rare Fish Auction.... fish that I've never seen before... for ridiculously low prices.
There were a couple of dozen raffle prizes...a lot of them $25, $35, $50, $75, $100 gift cards for vendors in the Marketplace (and with whom we did group buys and/or were sponsors).
And that's not even getting into the value of four awesome speakers, free beer and food on Friday and Saturday, free T-shirt, free goodies/samples, getting to hang out with fellow hobbyists, supporting the club, etc.
Matt