i've been going for a few years. i've gotten in for the past 3 for free by volunteering, but in order to get a free ticket, you need to have worked for a department for at least a year.
you're not going to be able to get in for free by being a first-time volunteer for any department, (which sucks), but you can get in early for volunteering with perimeter, gate and exodus (PG&E), or with the center camp, and probably a few other groups that i haven't yet worked with. DPW is probably full by now for early arrivals.
having worked with both gate and perimeter before, i can say that it's going to be pretty hard to sneak in- hiding in a vehicle being the easiest method, but a lot of folx are still busted this way. burning man actually uses a fucking radar system to patrol the borders, and start a week or two before the event starts.
friends of mine and i have always been pumped about the idea of organizing a mass break-in to the event after it's started, which would be made easier by coordinating with volunteers inside the fence.
as for paying to get in, yeah, it is expensive. burning man IS a multimillion dollar corporation, and the land the festival is held on is rented for a million dollars from the BLM. you can still apply for scholarship tickets at this point, i think, for $110 on the website, but ticket sales are probably at $250 or so by now.
hope some of that was helpful.