It really depends on the condition of your house and its real market value (sorry but Zillow often gets it wrong), how fast you need to sell it, and the type of “investor.” There are two main investors:
House Flippers
Rental Property Owners
Flippers usually pay 70% of the house’s value AFTER repair value. When they give you an offer, they estimate how much they can sell it for after flipping minus repair costs. These investors are looking for distressed houses.
Rental Property Investors usually prefer properties that require none to minor repairs, and they want a deal that will give them a monthly income of 1% of the purchase price. Their offer is based on how much they can rent it out and minus any needed repairs. If your property is in top shape and in a high-rent area, you may get market value for your house.