I posted on another thread how I bought a lovely 1 br with one parking space for cash...and it sat for three months,  is now rented to a marginal tenant.  

And the marginal neighborhoods are getting better. 

The same logic applies as in the case of wholesaling a house: establish a stable value (provided you know how to do that), subtract buyer's potential profit (e.g. 20%), subtract rehab & closing costs, subtract your fee (1-3% depending on the size of the deal and the profit margin).

Tight margins but maybe there is a way to get a better deal on other units. 

However what I’m taking about here is just putting down an extra 5% on this deal for a marginal rate or return of 8% on that additional 5% down payment.

The key takeaway is to run your numbers at safe margins so your not surprised when things come in lower. 

You are making numbers work to meet your profit margin.  

That way you can get all your money back and some profit and then go into the next deal with some better margins. 

So buy for 100k, but in 100k, and have it worth 300k, - now it's worth all the stress, energy, time, and money this will require... you're anticipated margin is too small to make this a good deal - unless the area is so hot you see the value appreciating significantly in all the next few years. 

Its hard to help evaluate your ARV or your rehab budget without knowing the location of the property as these both can vary by locationsIf by South Jersey you are referring to Camden/Gloucester/Burlington than here are some additional thoughtsYour Purchase closing costs should be closer to $3,500 not $2,000Rehab budget could be as low as $65,000 but I'd assume it's more like $80,000You should be planing for at least a 180 day hold 90 days to renovate and 90 days to market/sell/close$20,000 is also a pretty small profit margin on a house needing 65-80k worth of work.