You've got an Underwood Quiet-Tab De Luxe from the Golden Touch era. I wrote a blog entry about the machine which might be of interest to you. If you want to know the year of manufacture we would need to know its serial number.

Value varies from area to area, but it's not a rare machine, nor is it a pariticularly desirable machine for collectors, or even teenage girls who prefer typewriters with pretty paint jobs. If it's in excellent condition it would fetch in the $50 to $100 range in my area (Toronto).

Welcome to the forum by the way!