Quote from @Elijah Dominguez:
What I mean is that retail sellers, the ones you find on the MLS, are motivated by getting as much cash from their sale as possible immediately. They don't have a NEED to sell they only have a WANT as in: "I want to get rich off of the sale of my house so I can buy a bigger one." These are not the sellers you should be talking to if you want to make money.
Wholesale sellers, the ones you have to find yourself through marketing, are motivated by something else. They NEED to sell and they don't care how much cash they get. Basically owning their property has become a problem and they need you to solve that problem for them.
Spreading out the tax hit. Occasionally you'll find a seller like a retiring landlord for example who wants to avoid the huge tax liability of selling their portfolio for cash. This is a prime situation to get some nice seller financing. Seller financing allows them to spread the capital gains out over many years by reporting it as an installment sale.