Ruby Australia has existing accounts for the payment gateway Pin Payments, and the ticketing service Tito, so it is perhaps easiest to leverage these. No matter who you go with, though, you will need to factor in fees for both into your budget.
You will also need to charge GST for your tickets - due to the size of Ruby Australia's yearly income, it is required to collect GST. Again, factor this into your budget accordingly.
You will likely want to offer the following tickets:
If camping in tents is an option at the venue, and results in a lower venue cost for those attendees, you may wish to offer camping tickets at a slightly discounted rate as well.
Early-bird tickets are another option, though may be unnecessary.
If your venue is smaller than usual (holding fewer than 100 people) and a high demand is expected, there is also the option of running a ticket ballot: people can enter the ballot before a well-publicised deadline, and then tickets are randomly allocated. Previous camp organisers may have code you can re-use for this purpose.
When running a ballot, Ruby Australia committee should be given reserved places (if they wish to attend) for the purpose of the General Meeting that will take place.
It's recommended that you have a deadline for ticket sales of a month prior to the event. This helps motivate people to buy their tickets sooner rather than later, as well as giving you a better idea of how your budget's looking at that point in time, and makes it easier to confirm numbers with the venue and caterers.
As part of ongoing efforts to increase the diversity of the Ruby community, scholarship tickets are usually made available for people who wouldn't otherwise be able to afford a Rails Camp ticket. Recent camps have had an application process for this, and then awarded the scholarships by their chosen metrics.
There may be specific sponsorship funds available for this purpose - the Ruby Australia team will confirm. Otherwise, it's an excellent option for attracting camp-specific sponsors.