$5K credit towards replacing a 1300 sq foot roof

[Svend W.]

Hi BPers

I'm looking at buying a house in Chicago whose roof is intact and without leaks but very near end of life according to both the general inspection and a roofing spection. 

The roof is 1250 square feet and is quite flat

I initially requested a $10K credit and the seller (a flipper who recently rehabbed the house) countered with $5K.

$5K strikes me as a bit on the low side, but I don't know about these things. We got an estimate to replace it for under $5K, but the guy didn't strike me as terribly competent, so I am nervous about relying on that. (And Chicago is covered with deep snow right now, so getting a second opinion isn't easy right now.)

Assuming there are no other issues, does that that number sound overly optimistic? I realize you have to roll the dice a bit in these situations, but I'm wondering what the worst case scenario probably is cost-wise (again, assuming no other problems).

Thanks in advance.