It also obviously depends on whether the basement is finished (which can add value) or unfinished (in which case it may add relatively little value).
And it depends on the value of nearby homes. A basement in a home worth $600,000 probably will add more value than a basement in a home selling for $80,000.
Check with a Realtor in your area--and even specifically your neighborhood--for a more precise answer. Where I live (and this may not be at all reflective of your neighborhood, buyer expectations, etc.) a basement might add $10,000-$20,000 to a home's value, and maybe another $10,000 if it's nicely finished.
Hope that helps.
I agree with Carey on this one. I would compare this to the concept of a two bedroom home versus a three bedroom. Most buyers want three bedrooms. In Appleton most buyers also want a basement. So, in essence the value goes down because there isn't enough demand. Hope this helps!
Basements, here in WI and particularly in the Appleton and immediate Fox Cities area, do affect the value of a home. Although, every home has a "price" and homes that don't have basements do still sell in this area. One of the only exceptions are lake front properties, due to high water table levels. There are many lake front properties that do not have a basement and keep their value!
I would love to help answer any other questions that you may have. Please feel free to contact me directly.