Windows 8 to 8.1

Is it free to update windows 8 to 8.1 and if so is the process easy or do you need to be a computer boffin to do this?
Reason I ask is we need a new pc and I have seen the one we intend to get with 8.1 installed for £380 but also for sale with windows 8 for £30 less.
Should we get the more expensive one and be done with it, or go for the cheaper one and save some money which could go towards new software?
Whats it best to do?
Cheers

The upgrade to 8.1 is totally free and is as easy installing a Windows Update. If you've got two identical machines with 8 and 8.1, and the 8 machine is cheaper, get that. You have to fully update your machine with Windows Update then install 8.1 from the Windows Store (free). All you have to do is start the install and it takes care of the rest.

Windows 8.1 is a free and easy update from 8. Just run all the windows updates, then go into the store and the 8.1 upgrade will be right there.

Sounds easier than I thought.
Thanks for the advice.