Several free online tools let you easily convert your DOC or DOCX files to XLS/XLSX format. To name some, Coolutils and Convertio are some good free online Word-to-Excel converter tools.

If you don’t want to spend money on Word and Excel, there are options for getting these programs for free—options that are legal and above board, and offered by Microsoft.

Google Docs and Google's Cloud Connect toolbar for Microsoft Office combine to let you do simple editing of Word and Excel files on an iPad without having to pay for a separate app.