There are real costs ($$) associated with this that have to be covered.
Los Angeles is a unique city. It's huge, it has shitty public transportation not suited to 400 Santas in mass. Much of the public transit routes have been done - or are in areas that don't lend themself to 400 Santas. If you have ideas, then volunteer for the organization team next year. This year there were 10 new Santas co-creating the route you will experience on Dec 11.
What does the $20 pay for?
Every route, experience, unfolds. Along that, there are possibilities, opportunities, intersections that have been primed for Santas visit. Other intersections have not been primed.
Past costs have included games, refreshments, ponies, paying for drinks in bars, snow, buses, medals, trophies, carol books, jello shots (last year there were 350+), entrance fee to museum, tips, cases of beer, entry to afterparty clubs, etc. Last year the money was spent on two poines, trophies and medals for santa, 25+ pizzas delivered, jello shots.
What else do I need to pay for?
There may be additional <$5 costs for the route. This does not include any purchased food or drink. Santa must cover this on his own. Santa does buy drinks for Santa and often keeps Santa stocked in creative yet legal ways. Santa does not break the law. To keep your Santacon experience as cost effective as possible, past Santas have encouraged Santa to bring a flask. For less frugal Santas, bring cash in small bills to cover food and drink purchases. The venues open themselves up to us and we must behave respectfully in return.
It comes down to Trust
Do you trust Santa? Can you trust Santa? Is $20 an amount to build trust with Santa to magically surprise you with one of the best days of your life? A memorable event you can't wait to tell your friends. A day that possibly changes your life (if you let it.)
The Santacon experience is priceless. The only way you can "pay" for the experience is in your full and complete participation. The $20 covers the real world /economy stuff. Cover that, and we're free to experience the rest. You make the choice. The $20 is a small fee, compared to the impact on the rest of your life.
