While Microsoft's Windows Defender is pretty good for basic security, there's still a lot to be gained from using a robust, third-party suite. Today, Newegg has a great deal on a good anti-virus suite for up to three-PCs.
For $24 you can pick up AVG Internet Security 2018 with the checkout code EMCPUPY34.The purchase includes AVG, as well as Malwarebytes Anti-Malware 3.0. The license is for three PCs for one year. The checkout code is from Newegg's daily sales email circular, so you will have to supply the retailer with your email address to get the deal.
AVG typically sells Internet Security for $70, which is licensed for an unlimited number of PCs. That's a great price in and of itself, but if you only have a limited number of PCs—like three or less—this lower-priced deal is a better buy.
When we reviewed AVG Internet Security in October, we liked its performance, and the fact that it was a full-featured suite. The interface could be better, but it's still a great tool for protecting your PC and it doesn't put a strain on PC resources.