Head over to Amazon and grab this cheap deal for a Finish Dual Action Dishwasher Cleaner. It's priced at $4.99, but you'll score savings when you clip the Amazon coupon for $3 off. Then check out with Subscribe & Save for an extra 5% or 15% off. You could pay as little as $1.24 for one cleaner.
Note that you'll get the maximum 15% discount when you subscribe to five items or more and have them shipped to the same address. Read more about how Amazon Subscribe & Save works.