WPS Spreadsheets (formerly Kingsoft)
Libre Office
Open Office
Most computers and laptops have some form of office on them. Even the limited versions are usually sufficient to do most things.
I have been using WPS and Libre but recently discovered that I actually have Microsoft Office on my laptop. I never took the time to explore the layout of Windows 8 and didn't see it right away, so assumed I would have to pay for it, so I went with the free stuff, which I will more than likely stick with.