Best way to go about purchasing a cash only property

[Matt Tobler]

So through connections, I found a homeowner who's mom recently passed away. The son lives out of state and wants to get rid of her property as fast as possible. He's willing to sell me the house for 55k cash. Its a great deal considering the house doesn't need much work at all and the comps around there are selling for 150k-170k. His mom was an extreme hoarder and he doesn't want to deal with having to clean it out and list it. He just wants it gone. I reached out to family members to try and get the cash to purchase it and told them id finance it as soon as possible but had no luck. My question is what is the best/cheapest way to go about getting the cash for this property? 

 id like to start my rental portfolio and feel this would be a great first property. rental rates for 3/1 in that area are going for 1400 and there is also room in the basement to add a additional bedroom which would juice up the rental rate to 1600-1800!