All around the map in every city at points called "Travel Agency " or some title similar
The travel agents selling the tickets will lie, and use other ways to get the contract signed.
A travel agent will offer you a chance to go on an all expenses paid trip to @The Fortress of the Feather The cost is 5gp payable to them. But the rest is covered. The sales person just has to have them sign a contract.
DM direction, this information is only shared if the person reads, the contract. The contract for each person on the trip is really a hidden slavery contract for 10 years service and debt of 15,000gp. The money for the sale going to the travel Agent. The @Red and Square Travel Ticket which is modified to have the sellers name on it, is a receipt who connects the agent to the payment by name. The agent will lie about the vacation to try to make the sale!
The ticket is collected, and the person's name on the ticket is credited 10,000gp. The traveler at the booth will have a debt added to there names of 15,000GP which is processed in a computer termal at the booth. An agent then takes the travelers on a tour to @Room 0 is the general holding room there they are locked in cages.
If you press an agent they can offer you the ability to sell "contracts" to others. They will give you a sample contract, and tickets. They will tell you to add your name to the tickets and tell anyone you sell them to to give the tickets to the agent at @The Fortress of the Feather