Sanford(R) Prismacolor(R) Professional Art Markers, Primary/ Secondary Colors, Set Of 12 for $27. They aren't cheap, but wow a good marker makes all the difference. Normally, I prefer to sketch, scan, and color in Photoshop, but sometimes you need immediate results. The good thing about starting small with Prismacolor sets is you can buy wild colors that you enjoy using individually (as well as the blending marker for gradients). These markers also come in a brush-tip variant.
Quint Graphics Mini Dusting Brush 10" $4. If you are going to use a cleaning pad / bunny bag / powder sack, you will need a brush to softly remove excess from your drawing otherwise the occasional chunk of overly large residue from erasing or smudge-proofing can hamper your ability to draw, or worse, erase an area with detail by being pushed by your lead inadvertently.
CanoScan LiDE 500F. These are hard to find now, but you might find one at Best Buy or Fry's in the $75 price range. What makes this scanner so wonderful? It can sit flat or stand vertical, leaving you with more desk space; however, the primary reason I love it is that it draws power from its USB cable, so you can use it with a laptop.
Don't be an ogre. Shape your pencil edge, don't just sharpen it. Use the Sandpaper Pencil Pointer from Amazon for under $4 and you will stop burning through pencils every time your drawing demands shading (without resorting to giant smudges with a tissue stick).
Amazon.com: DRAFTSMAN'S (DRY) CLEANING PAD 3oz. $4 This is an old-school drafting tool used for either softly removing smudges, or making fine pencil drawings smudge-proof. In the latter usage, when a drawing is complete, softly drop the bag around areas with the greatest detail to keep them from smudging in the future (due to rubbing against other paper, exposure to moisture in the air, etc.) You will only ever need one bag so don't go crazy and buy a 6-pack. Those are for classrooms.