It looks like you can get VMware Fusion 5 using the following discount code: "fus5beta20"
You save $10.
I upgraded to version 5 standard from version 4 for $39.99, a $10 savings.
Not sure how long this is going to last so if you wish to upgrade to version 5 and don't want to pay $49, this is the way to do it.
I believe this works for both the Pro version and the Standard version.