Enter auto show contests for free tickets leading up to the event, listen to local radio stations for a chance at auto show ticket giveaways, ask your friends if anyone has an extra ticket you can have, and visit the auto show website to check for free ticket opportunities. Tickets are more likely to be given out for free as the event draws closer, if the paid attendance for the auto show appears to be low.
Auto shows always need help with promotion, so consider volunteering for a street team before or during the auto show to get possible free admittance. Street teams hand out promotional materials, take pictures and engage the public in creative and interactive ways to boost public awareness for the auto show. Promotional teams inside the auto show do the same type of work to generate publicity for a specific product, brand or vehicle. For example, the local CBS affiliate in Washington posted pictures to its website in 2015 about the Washington Auto Show that were provided by a promotional street team, and street team members often get to be inside during the show.
Auto shows typically have a lot of sponsors, and those sponsors sometimes offer deals on admittance to the auto show that are somehow connected to their product. For example, you may get a free ticket to the auto show if you purchase the product of a major sponsor beforehand. Some auto shows are also sponsored by dealerships that have a small number of tickets to give away on a first-come, first-served basis.