I had a quick look at the web app feature (Office 2013) available via skydrive and for simple spreadsheets it looks like it could well do the job.
But be aware that if you are using an existing book created in the desktop office application and use advanced functionality - macros, hyperlinks etc. and post it to the cloud, then I found it seemed to come unstuck and those features wouldn't work in the web app version and I had to take the option to open the book in the desktop office product.
Even when creating a worksheet in the web app itself, there appeared to be nowhere near the full functionality of Excel.
I must concede that my testing wasn't thorough but I was disappointed with my initial results.
Am keen to see what others have experienced.