You cannot receive money from disenchanting directly. 

The "Disenchant Value" listed on thottbot takes the average materials that drop from the item and adds their AH prices together.  For example:

Say you have a level 15 green sword.  You can sell this to a vendor for 5 silver--this is the vendor price.  This sword typically sells on the AH for 75s--this is the auction house price.  However, you can also disenchant it and you'll typically receive 1 greater magic essence, which (according to thottbot) sells on the AH for 90s--this is the disenchant value.  Keep in mind that this DE (disenchant) value is very server-specific.

When you look on thottbot for this item, the values will be:
Vendor: 5s
Disenchant value: 90s
Auction value: 75s

So, in this case, it would be smart to disenchant.  In reality, there are very few items where the DE>AH values, so making money here requires more AH skill than just removing, Disenchanting, and relisting.