Yes you can. You need to set up the "Mobile data usage" on your cell phone. This will allow you to set a limit ,setting up alerts for when you get too close to your limit, tracking all members you might share a plan with, or tracking usage on single or multiple devices. This free setting is available for both iOS and Android devices.
For your computer you can install a software monitor like cucusoft net guard which will also allows you to monitor your broadband usage and set limits where you want.