You only need an iOS device to setup your HBO Now account. Only the sign-up process is part of the 90 day exclusive. All you need to do is use a friend or family member's iOS device to download the HBO NOW app and setup your account. Once your account is setup, you can access the HBO NOW content from any web browser and even CAST the content to your TV with Chromecast!
Watch Game of Thrones for free! (for 30 days).
There is a small catch. The free trial only lasts 30 days. After that, your friend (who you borrowed the iOS device from) will have to cancel the account or start paying $14.99 per month. You could always give them the $14.99 next month so that you can watch Game of Thrones and Silicon Valley next month and most likely pony up for the following month too.