Amanda,
Your question has many variables, and there is not an easy short answer. Cost of land, type of building including materials, finish out, labor, quality and other factors will determine the cost. It will probably be less expensive to find an existing building that will serve your needs than building a new one.
You can start by finding a Realtor who can give you comparables on similar buildings in a location you desire and can connect you with a commercial builder so you can look at your options.
Dan Grimmett, Broker Associate
Jackson, MS
dan.grimmett@crye-leike.com

I know an appraiser there who might know...at least with recent comps and all.

If interested let me know!

Denton Ward
denton@nwrei.net