Adobe Reader is a free application that now allows you to type simple text into existing PDF forms. As long as you aren't planning to modify the form itself (by this I mean resizing text boxes or modifying column widths, etc...) you should be fine using the PDFs. You won't need a printer or have to pay for any software to do this.
Note: Before you use the text entry tools in Adobe Reader, you need to "sign" the document. Adobe will place your signiature in a spot you click with your mouse.
I don't have access to a printer ... and can type better into my computer than writing when on public transit (the only time I have to fill in the activity schedules, etc). Just thought I'd ask?