Looks good on the outside but inside it's a MAJOR fixer-upper; slanted floors, former tenants evicted and likely trashed the place before they left (it's disgusting).

If you do acquire the property then the profit potential is much better of course. 

I think I can get it from them for 20k, but I might be able to work out a % of my profit at the end and transfer title to me for free.

Don't count your profits yet as the tenants aren't gone.

What pass your likely profit for each scenario? 

It's my understanding that hard money lenders aren't necessarily the formal businesses you might find online, but simply any person/entity willing to provide a short term loan, collateralized by property, and willing to take (mostly) interest only payments and defer full / majority repayment of the principal upon the term end.

I would recommend that you sell the property for as high you can as long as the market will pay, while at the same time leaving just enough margin for the end buyer to make a the deal profitable for themselves and be happy at the end of the day.I see many newer investors leaving money on the table because they think small and sell the properties by asking themselves " how much would I be content making on this deal?"

The property is vacant and dilapidated because the owner is so far underwater that it no longer makes sense to maintain in the vast majority of situations.  

Baring any major unforeseen issues would allow for a bigger profit on a flip.  

Which would you rather have: 10% of 100k or 20% of 30k in profit?