I've run a small competition for my club (less than 40 entries) and the answer is no. It depends on how you're managing your costs, but with the typical $7 entry fee costs add up pretty quickly. We hold it at a brewery, usually starting a bit before they open to the public, so I like to throw some cash to the servers for their help and time. Even if we're cleaning up after ourselves they're still helping us with something.
- Competition hosting software ($30 unless you're hosting your own)
- Cups, labels, water, pencils, crackers ($25)
- Judging amenities (Snacks/food, swag, coffee, water ~$50)
- BJCP fee $25/30 (BJCP members/Non members)
- Calibration beer for judging ($20)
- Tip/thanks for servers (If held at brewery ~$50/2 servers)
- Prizes? (Can usually get these donated)
- Total cost ~$200
If we get ~30 entries we're making about $30, which disappears pretty quickly if I've underestimated some of the costs. If you save some of the consumables (unused cups, pencils) and can host the competition software yourself then maybe you can cut the costs down and make a hundred bucks. It's not really why we do it as a club though, and I'd rather take that money and put it into judging/sensory education for the club. When you start getting bigger than you need to start worrying about where you're going to store all the beer as people drop it off as well.