Where to get promo codes for McAfee products?
You can get coupons for McAfee products using the available websites listed on Google. There are plenty of those. Basically, get the coupon and apply it when you're buying the application.
The company itself provides a page with Promos for users: http://promos.mcafee.com/Offer.aspx?id=439873
Google Search listing for coupons: https://goo.gl/wezJmS