There is a $10 MIR for the MX500, bringing the price down to $8.95, plus shipping. The problem with JustDeals.com is that they charge $12.90 for shipping, which we all know is high.
The total, after shipping is $21.85.
The rebate is listed at:
I just bought it from JustDeals, but make sure you check the rebate if you choose to buy from somewhere else.