I own a copy of Office Home and Student 2007 but I saw that Microsoft offers a Microsoft Office Starter which is apparently a free version of word. It's obviously newer than 2007.
Then there is also OpenOffice and other free office suites.
I don't know anything about them, which should I get? I assume that the Office Starter is very limited so my 2007 version is probably better. What about the other free ones like OpenOffice though? They're obviously updated for free. Would it be wiser to use those instead?
Give OpenOffice a whirl and see what you think to it. It will almost certainly be a more rounded, comprehensive suite of applications than the Microsoft Office H & S you currently use. It will also give you a chance to see just how compatible they are regarding file formats.
And, as you indicated, you can keep OpenOffice up to date with the latest version all the time, something you probably couldn't afford to do with Microsoft Office.
Office Starter edition is not sold at retail, it is only offered on new laptops / computers. So, keep using your Home&Student edition, moreover - there are good chances it is three-user version, not a single-one.