As a $10 backer I received my key without issues.
However, as I realized it was a single machine key, I went on and try to get an additional license for my second computer.
Then I found out we actually have to pay more than non-backers for multiple PC keys. I'll explain here.
First, here are the current costs of the licenses:
1 PC - $15
2 PCs - $23
3 PCs - $30
Now as a $10 backer, if I wanted to get an additional license. I would have to buy another key for $15.
That means I would have spend $25 in total for a 2 PCs license.
And if I wanted to get yet another license. I would have to buy the $23 option for 2 PCs.
Now I would have spent $33 for a 3 PCs license.
Here is the summary of costs for backers.
1 PC - $10
2 PCs - $25
3 PCs - $33
4 PCs - $40
I am sure backers would appreciate a discount for additional licenses!