Spend any time with Esperantists and you discover how important conferences — kongresoj — are. I think it’s because the community is so small that it helps to have intentional times together. That, and since one of the language’s selling points is your ability to speak with people from other countries through a non-national auxillary language, international travel is a frequent option. Little wonder that the word for registration form shows up on beginners’ wordlists.
No doubt due to the lack of sponsors, the likely fact that most attendees pay their own way and the long duration of conferences (perhaps due to custom — Esperantists have been doing this for more than a century — and the long distances traveled) great attention is made to keep costs down.
Discounts routinely go to the young, persons from particular sets of countries and early registrants.  The lodging costs are often very low — with comforts to match. Room-sharing is routine, and camping and floor-space accommodation (bring your sleeping bag) are well-known. Meal plans are common, and a vegetarian option is a given. Some conferences allow for cooking, and I even noted a United States conference info page that tacitly apologized for this option not being possible.
It’s possible to have a private room with a private bath. There are sometimes banquets and very often day trips. There’s little to help the cost of very long distance travel. One can spend money (and donate money to help offset others’ costs) but a conference trip, doubling as a modest and interesting vacation, is kept as affordable as possible.
A couple of examples. The Universala Kongreso — the big international conference at the end of July this year — is in Copenhagen: a very expensive city. A 29-year old attendee from Poland, who is already a member of the Universala Esperanto-Asocio, registering before last December 31, would have paid €60 for the 8-day conference. Even my late-registering, non-UAE-joining, forty-something United State citizen self would only pay €300, which doesn’t seem unfair for occasion.  The whole conference in a college dorm share with one other is €190. No word about self-catering.
Or you can go to the Christian (mainly Protestant) Esperantist conference (PDF, in Esperanto, of course) the week following in the spa town of Poděbrady, Czech Republic. Our early booking Polish friend would get this 8-day conference for €160, shared room, meals and (perhaps) day trip included.
This is a long way around to saying that there’s nothing wrong about counting pennies when putting together a conference if it means more people can attend. I’m thinking of the next General Assembly. My first was was in Charlotte. I got the young adult rate, a shared room (thanks I think to Joseph Lyons) but had to live on vending-machine Cokes for three days because there were no grocery stores within walking distance and the restaurants were full and expensive. (I think the area is more built up now and in any case there’s a light rail system that did not then exist.) One dear minister — no longer with us on Earth — bought me lunch, under the excuse I’m sure of examining my interest in the ministry. It’s largely because of the experiences at the 1993 General Assembly that you have me today. So when I organized a seminarians’ breakfast the next year in Fort Worth, I found a place that everyone could afford, even if it wasn’t fancy.
Costs matter if people matter.
