If they don't want to make they payments, they need to sell it, make up the difference, then walk away.If you want to turn around and sell the house, you'll need a significant discount in order to make money after all the purchase, holding, and sales transaction costs.

In about 95% of all cases, it builds in an automatic discount without me ever having to negotiate.

@Christopher Persaud some tips I can give are look to buy discounted gift cards or coupon codes for the big box stores.

Tile, flooring, appliances, fixtures are all massively discounted.

Are they primarily doing flips and paying cash for deeply discounted props?

Buyers ONLY pay top dollar for a finished product.A busy street will discount some but I feel you have a lot of other issues with this property that are more pressing.

If you plan to play in this space, I'd be looking for a steeply discounted property.  

I would want to know for sure ahead of time what is going to happen if someone claims they paid rent in error or something of that nature.A standard credit card vendor could work if you are willing to pay the fees associated and accept the liabilities associated with that.The easiest solution (and what I do) is to offer a "rent discount" for tenants who pay using direct deposit.  

Hey Check out The Real Estate Negotiating BIBLE, seems to be pretty on point with getting sellers to take a discount.https://www.amazon.com/Real-Estate-Negotiating-Bible-discounted-ebook/dp/B01B5H0U2E?

And it gives you an excellent reason to discount the price, as many will be wary of such a cloud on title that they won't extend any offer.