First time traveler from US - Visa Question

This might sound like a silly question, but can I stay in Thailand for 90 days without applying for a visa? I've read that you can get visa exemption for 60 days with a 30 day extension and I'd just need to show passport, proof of funds, and possibly proof of housing/return flights on arrival. Information I can find on this is pretty foggy with changing laws. Any help would be greatly appreciated!