Welcome to the Guild Amunak. There are tons of great GIMP tutorials here, and a few good Inkscape one's as well. And yes, it is possible to make some really nice maps without having a tablet. As to your question about the 5-post limit, there is a very simple solution to your problem: just write three more posts. Seriously, all you need to do is browse the finished maps section for about 15 minutes and give kudos to the people whose work you like. Done.

Cheers,
-Arsheesh