It will take on average about 3-4 months to flip and then out on the market and sell. You'll be paying whatever mortgage and taxes on that property the whole time during the flip. Then you still have to sell and still have all those costs.

Can you do any work on the house yourself? If no then you'll need subcontractors to do the work and that increases your costs as well. As with most flips in general or houses people buy at auctions or foreclosures you probably won't notice any issues until you start working on other things. Then you notice the he electric and plumbing isn't up to code. And it goes on and on.

A good rule of thumb is to use 20% of the cost of the house to have as your breaking point. For example a house you paid $100k that you are trying to flip, you would want to sell it for a min of $120k to break even on flipping costs, taxes etc..

Obviously not every house will be like this but there's risk with every investment. "The greater the risk the greater for the potential of reward"