water slide decals and paper

The last discussion I remember on making decals was here.

As far as scanners go, most inkjet printers that I'm aware of, have a pretty decent scanner built in, compared to what was available years ago. At present, I have a Brother MFC-J480DW inkjet printer and I've been very happy with it's scanning & printing abilities, YMMV. It prints water slide decals pretty fair for me, resolution wise. It will print a legible thin script type font less than a 1/16" tall. I think you might consider needing a pretty decent graphics program for helping to manipulate your images. I use Flexi 8.0, left over from the ol' sign shop days and it makes life easy. I know there are some pretty capable graphics  programs available for free download but the learning curve can be a bit more than with a commercial version.

Good luck with your pursuit!