On Tuesday, Dish Network's Sling TV will open its online TV streaming service to those who had requested invites. A full launch is expected in about two weeks. The package is cheap - at $20 a month - compared with cable and satellite packages that typically cost $50 to $100 per month. Sling TV's base package comes with 11 channels including Disney, Turner and Scripps. There are two add-on packages, for news and kids that cost $5 each. All subscribers will get ESPN. The service will first be available on Apple and Android mobile devices and the Roku 3 streaming device. Although it's a bargain, there's no ability to record shows for later viewing.