Is there anything stopping the club from selling memberships on eBay? Why not run an ad for qty 100 memberships with a Buy-It-Now price of $30 (each, obviously) and let it "run until sold". Unless there's some special vetting process used to keep people out, this should work just fine. For pictures, show the types of things people collect, pictures of the annual convention show floor, speakers talking, raffle winners, local group meetings, pictures of members standing in front of old, long-gone casinos, postcards of "the way things used to look" (like Stateline at Lake Tahoe), and so on. Be sure to include keywords in the main listing like "chips, ephemera, [popular collected items], collect, rare, casino... words that people searching for items to buy might include and get us some additional hits.

Might be worth it to pay to be a sponsored listing. I don't know how much that costs, but it could be tried for a while to see if it generates any additional leads.