We usually have a coral of the month. We try to get the shop that is hosting the meeting to either donate the coral, or give it to the club at cost, and then we sell the frags for about $10 each or per polyp depending on the coral. Last month was Duncans for $10 per polyp.
We also have sponsors that donate food, additives, and equipment that we sell raffle tickets for. Sometimes members will have tanks and other things they no longer want and we can raffle those off as well.
The only other way is through the membership charges, but at $10 per person for the year, and only $5 if they sign up after June, you will not make much on that deal.