The substantial cash need for large down payment or all cash that most others don't have .

@Peter Mckernan Copy.... it's a "% based payment" off scope of work. 

Prepare financially by saving for down payments, improving your credit score, and setting aside emergency reserves.

I use credit cards, write checks, and pay in cash.Each situation can dictate the payment type. 

If you're a single mom with student loans, a car payment, and living paycheck-to-paycheck, then $20,000 would be devastating and a reserve is critical.

@Tonya EnglishWithout a clear understanding of what this company does (or more accurately, does not do), the payment seems excessive compared to other services in the market."

Cash Payment: Decide whether you'll finance the purchase or pay in full.Future Resale Value: Factor in potential appreciation of the property.2.

Maybe a better question would have been if you know how much money you have for a down payment on a property? 

Instead of a traditional down payment, I would give them some money (maybe just to bring the loan back to even).The upside if taken over the loan at the current balance, with some rehab and hopefully getting the front lot back would be a nice ROI. 

You end up having to sell to someone with higher down payments, better credit, better operating plan, and 100% investors who never want to pay top prices.