Card games was the second thing that came to mind. Sure, you can buy packs of cards for a couple of bucks, but that one card you need to complete your deck can only be found on collector sites or ebay for $150. Oh, you’ll need 4 of em. And different ‘key’ cards for each of the 10 decks you’ll want to try out. Sell them when they don’t work out? Burn the heretic! I might come up with a different configuration they’ll work in.
It was second only because I have it by word of mouth, never been far down that road. The first I thought of was miniature tabletop gaming. First there’s the miniatures and sourcebooks. Then you have hours painting them. Then you really need to build a terrain table to play on (think model railroad for different geeks). And display cases for when you’re not playing them. wimper.
Get thee behind me!! Local bookstores have called me when they need to make payroll.