Depends on what you consider "cheap." The Open is in a very pricey area. I would recommend looking either downtown Tempe at one of the Marriott hotels (there are several) because they often offer an airline rate if you want to be near bars/restaurants. The airport hotels are the least expensive at this time of the year and a pretty easy drive to the event. Also, consider looking at Chandler hotels as it would be a straight shot up the AZ101 freeway to the event. Not as walkable as Tempe but less expensive.