Here are the apps that I currently use to save blog articles to read it offline:
Procket is free to download from Applestore and Google play. It will help you easily save articles, videos, and other web content to read later even when you're offline. It syncs with your smartphone, tablet and PC.
DOWNLOAD Link for iOS DOWNLOAD Link for ANDROID
Instapaper costs $3.99 in appstore while it's $2.99 (134.45php) in Google Play. When you find an interesting web page you’d rather read later, save it to Instapaper then read it wherever, whenever, even without an Internet connection. Features include: text-optimized viewing, adjustable font, browse feature and social media sharing options.
DOWNLOAD Link for iOS
DOWNLOAD Link for ANDROID
Screenshots:


