Zoolz Cloud is offering 2TB of Data for Life for $50 - https://stacksocial.com/sales/zoolz-cloud-storage-lifetime-subscription-2tb
https://home.zoolz.com/
This sale ends in 4 days but it looks like they offer discounts here and there if you look around.
Use Android Police's coupon code for an additional 15% discount - APZ15
You basically buy a license and it gives you a set number of users/devices that can connect and the amount of storage that you own.
Pros:Easy to back my two devices up to the cloud (windows/mac)
Cons:Check which license you are buying to make sure it gives you what you are looking for