BiggerPockets

If the purchase price plus the rehab costs for a fix and flip is 70% of the ARV, your profits will be in the 10-15% of ARV range.

Yes, that works in any market. Its just math. What changes is the LTV a hard money lender will do, and the ARV you can really get. If the market is declining, as most are, you have to discount the ARV from what it is now to what it will be when you sell. Reports just today say home prices have fallen 18.2% in the last year (Nov 07 to Nov 08). So, you would want to discount an ARV computed from recent, nearby, similar comps by about 10%, at a minimum, if you think you can sell six months from now.

That assumes you have hard money, and hold for about six months.

If you can borrow 70% of ARV, you would still need cash to do the deal. Maybe 10-15% of ARV. If you can get purchase and rehab down to 55-60% of ARV, you might not need so much cash.

Some HMLs are using lower LTVs. Some are requiring you to have money in the deal.

If you're wholesaling, you would need to subtract your fee out of the price, too.

Another good way to determine what buyers are buying at, is to know at what percentage of ARV hard money lenders are lending at. Most buyers these days use cash, but hard money is the same as cash. This will give you a good idea...