And, FWIW, I just do my drawings on plain old printer paper. I haven't used my home inkjet printer in literally years — I don't even know if it still works! — but I do still have a couple reams of its paper sitting on a shelf collecting dust. Might as well put a few pages to good use.
Once I'm sure my ink is dry, I just slap it into my USB document scanner (sitting unceremoniously on the floor next to my desk) and go to town in Photoshop.