My office came with a desk that has two adjustable surfaces--not readily adjustable, mind you; it requires schlepping and an Allen wrench. So since I always type with the keyboard in my lap when sitting, I raised the main surface a bit, and when I work standing, I just put the keyboard on a box that my business's stationary came in, tilting the box a bit forward for an optimal wrist angle by slipping a few thick magazines under the box. It's totally jerry-rigged, but totally cheap (free) and quite effective.
Off-topic: I have been using Pomodoro (Mac) to time my work/break times, and have been meaning to slip in push-ups and stair sprints during my two/10-minute breaks, respectively. Hasn't happened yet.