On July 22 Macrium posted a 10% coupon to their Facebook page: https://www.facebook.com/Macrium I just checked and it still works.
You're right. The RetailMeNot 20% coupon doesn't currently work, which is why I linked to the 10% coupon.
I'm amazed that someone responded to this. Do you really need the paid version? It's pretty expensive for me but the FREE version works great. If I was rich I would definitely pay for it but I have four computers.
I agree. For most home users, the free edition would be everything they need in a backup solution. A feature comparison is here: http://www.macrium.com/reflectfree.aspx The free edition is what I recommend to my friends. However, the free edition is licensed for non-commercial home use only. For business use, I pay for the full version and use whatever coupon happens to be available when I make the purchase. So I was happy to provide the original poster with a link to a coupon.
I make a backup of a family member's PC by cloning the entire hard disk to an identical hard disk in an external SATA enclosure (when something goes wrong I just have to physically swap drives). When I did this with the software of a competitor it took almost 2 hours every time. With the Rapid Delta Clone of Macrium 6 (only available in the paid version) this reduces to less than 15 minutes. Definitely worth the purchase price for me! (the RetailMeNot codes did not work for me either. I used a 10% off discount instead)
I have 4 computers which is why their 4 pack is a good deal. And yes the free version works great, but the paid version works a whole lot better. You do get what you pay for.