We had been borrowing trailers from parents, mentors, etc until last year. We applied for a local grant and got it. That along with some fund raising let us get our own trailer. A mentor with twins on the team owns a sign shop so he put our logo on it and it makes a lot of difference in team pride and just the ability to get our stuff to the event with as little issue as possible.
As for transportation we are blessed with enough mentors to be able to carpool. There are some full cars but we have been able to make it work for us. The exception is world's and even that could be carpooled. We just wanted the shared experience.
And because we never get to show off our trailer here it is. The picture is dark to show off the letters that glow when headlights (or flash bulbs hit it)