@Donny Long There are so many variables that a hypothetical answer would be virtually meaningless.
What if you find a very distressed property that is $12,000 asking and it's potentially worth $65,000 ARV, it's a great deal, right? What if it's a triplex that needs three of a lot of expensive things, asbestos abatement, discover there is soil contamination because it used to have a small gas pump and holding tank under the driveway from when the 3rd unit used to be the driver's quarters in the early 20th century and it's leaking into the earth (I've actually come across that) and it totals way more than $65k? And the list could even continue.
That's why you have cities selling $1 houses and streets lined with dead assets. To bring automotive lingo into it, that house is "totaled."
If you want to know your max purchase price formula it's: ARV x .7 - Cost of Rehab = Max Offer
But the overly dramatic example I gave (sorry... but it can turn real quickly) is why you have to know that cost of rehab with some degree of certainty, or else simply asking what percentage of 65k would make it a great deal is irrelevant. Labor costs are different everywhere you go. Materials cost more or less depending on where you are. RE markets are regional and trends are different everywhere you go. But you have to know those variables for the market you want to invest in and there really is no shortcut around it.
I hope that helped, and good luck finding a great deal!!