http://www.wallypark.com/DIA/landing.html
WallyPark offers 25% discount for AAA members (about $8.20). My company gets a 30% discount, so I pay $7.95 a day, which makes it cheaper than USAirport Parking. The perk is that it's super close to the airport when the Pikes Peak lot is full.
Also just noticed that you can bring in a competitor coupon and park for $7.95/day.