Background Checks Resource

I bought a foreclosure on the courthouse steps and I am getting ready to rehab it and hopefully rent it out for a while. I am trying to determine how much I should spend on this rehab.. I went to this blog www.biggerpockets.com to see what they say. They seem to know a lot about this sort of thing. I know how to do the tenant background checks and credit report when I find a tenant but not to sure about rehab spending they seem to be quite knowledgeable so we will see what happens.