As of January 2015, Goodyear offers oil changes starting at $19.99, according to their official website. National Tire and Battery also offers an oil change deal for $19.99 plus a $3 disposal fee if you make your appointment online, as listed on their website.
Meineke's website lists oil changes beginning at $24.95, while Walmart's lists them starting at $26.88, and Pep Boys at $31.99.
The exact price of an oil change depends on a variety of factors, including location, other services offered, vehicle make and model, and oil type. As evidenced on Goodyear's website, synthetic oil typically costs more than conventional oil.