When you want to create a drawing from scratch with a computer art program, you want an actual art program - not a glorified photo editor. Cheap editors are easy to get, since everyone edits photos. Decent art programs are not so plentiful, but there are some very good free and affordable options, and you don't have to put up with some lame old 'Paint' program.
1. The Gimp
The Gimp is an open source, free software program - this means it's legally free to use and modify, so you should give it a try. If you've used The Gimp in the past and found it unfriendly, give it another try - the latest version is full-featured, stable and has become a lot more intuitive to use. Controls can still be a little complicated, but the upside is a level of flexibility that many proprietary programs don't have. If you're new to this type of program, check out the many tutorials that are available (make sure they are recent ones), so you can learn how to use layers properly and find all the features you want. Find information and downloads at Gimp.org
more about Painter Essentials or download it at the official Corel Painter page.
Artrage has a really delightful interface, incredibly easy to use. I love its paper selection, and the overall experience of using it. Artrage is great for kids or people who are more comfortable with paper than pixels, because it feels almost like working at an easel. Don't be fooled by its simplicity - you'll find many serious artists using it too. The creators aim to give the artist a seamless, natural media experience and I really think they've succeeded. You can use tracing paper, and choose mediums and colors from large tuck-away palettes. The full version allows you to pin references to the side of your drawing space. Download a free non-time-limited starter edition, or try the full edition for 30 days. If you've never used graphics software before, try Artrage, you won't regret it. Here's the link to the Artrage website.
For creating vector graphics, Inscape is what you want. It's open source, so totally free, powerful and flexible. Like most drawing programs, it rewards you for spending some time checking out the manual and tutorials, but once you've got the hang of the basics, it's quite straightforward to use. It's particularly useful for converting raster (pixel based) images like jpegs to scalable vector drawings. It's easy to do - find a tutorial here. Follow this link to Download Inkscape
Sketchup is a great free 3D drawing program, with lots of fun features. It's not simple - 3D programs never are - but comes with a fantastic tutorial popup that opens beside your window, offering visual, animated tool tips as you work. The software has a very active community and you can download all kinds of finished objects and buildings from the Google Sketchup 'Warehouse'. If you are doing anything with landscape, building or interior design, or just want to play with perspective, give it a try. For under $100 you can go for the fully featured Pro version reviewed here - getting a little more expensive, but the results look impressive. You can download it direct from Google Sketchup