Do not attempt to print anything out from Gimp. It Does Not Work very well. Render it to PDF first.
As far as free software goes (in the FOSS sense, rather than the strictly literal send-no-money-now sense), the GIMP is pretty damn good. However, as free software tends to be, it’s designed (in the usual loose sense of ‘designed’) by programmers and ideologues rather than by domain experts. It’s extremely good for just about any casual purpose, eg. web graphics or home inkjet work, but just doesn’t have the tools for pre-press or professional design work.