You may be able to get the Sunday ads either a day ahead of time or early on Sunday, before the majority of the population gets them. By using the Internet as a resource, you will be able to expand your options of what ads you can look at, that may not be in your local Sunday newspaper. Going the online route will also personalize your options, so you won't have to sift through ads that you may not want.
Sign-up with the retailer to have them send their flier to your email address. Virtual ads are sent to your email address usually early on Sunday morning.
Visit the retailer's website. Some virtual ads will be up on the website at midnight Sunday -- and depending on where you live -- you may be able to access these early. For example, if the ad is up at midnight Eastern Standard Time, you may be able to access it at 9 p.m. on Saturday -- if you live on the west coast.
Subscribe to the weekend newspapers. Sometimes you will get early editions on Saturday that have ads for Sunday in them.