Short Sale-Offer Price

[Dan MacDuffie]

I am interested in making an offer to purchase a house via short sale. The house is in pre-foreclosure. I am trying to figure out my offer price. The house foreclosure est. is 52000 and the zestimate on Zillow.com is 87000. My realtor suggested an offer of 50000. I think the house needs 20000 worth of work. How do I decide on an offer price and do I need more information. This is my first real estate investment- my goal is to fix and flip. Thanks for time- Hadlock