I think i had heard someone say that there is a general estimate for such, and i think it was $17 psf. for an average bread/butter house. that comes to $25,500. And that sounds about right assuming you dont go top notch on all the fixtures and furnishings - more mid-grade, or some might call it contractor grade. You could spend a little more on some of the special areas, like baths/kitchens, but dont get TOO carried away.
Now this type of estimate is ok for making ballpark offers - but then, if someone likes your offer, then you can go ahead and do your due diligence (repair estimates by contractors, subs or a good general handyman and if need be bring in a roofer/foundation if those seem to need attention), and possibly even an inspection if the estimate comes out to fit the numbers.
What you do after that depends on your exit strategy, which may depend on your experience level in part!
hope that helps.
Cindy -
if you still need help or have specific questions, my email is cindy@dfwreiclub.com - and we can possibly exchange ph. no's.