GIMP is my new goto for editing pdfs, not as good as the real thing — it edits by drawing graphics over the page — rather than typing in forms on the page — but for filling out basic paper forms it can work well.
1) save pdf
2) open pdf with gimp
3) pick your resolution (100 pixels can work well for basic stuff)
4) draw on or, type on your page
5) export back to pdf — can even overwrite the orig file.