Numerous offers on property

[William Ware]

This is a the second property that I've found that I'm interested in and on the same day as it was listed the Realtor has informed me that there are several offers on it. This example is a 3/2 SFH in a great neighborhood in the metro Detroit area. Asking price is $21000 and comps in the area are low 90's for the same sq feet. My question is "How much over the asking price do I go?" This would be my first flip but my back up plan would be to lease. Here are a few of my estimated numbers.
Tax- $3700
Rent - $800-$1000 (if i decided to hold or due to the slow market)
Rehab $8000
My plan is to offer $25k with a ceiling of $30k

Bill