I finished rehabbing the property and got it under contract pretty quickly. 

I currently have a rehab project underway and it's financed with a hard money lender.

I have two options in front of me either to obtain a rehab loan, which will cost me $10k for six months ( points, fees, interest) or just finance the entire deal with my own money (cash).The rehab loan will enable me to obtain an additional property, so in six months i'll have two properties ( one with the loan, another with my cash)  but it'll cost me an extra $10k (on top of the regular down-payment which in any case i'll have to lay out) .

I've worked in construction (renovations, rehabs, residential prop mgmt, electrical) for 13 years and I'm looking forward to learning more about financing the implementation of that experience into a fix/flip and/or rent program as well as meeting new people to collaborate with.

Rehab lenders and construction lenders offer Lines of Credit.

I think one thing you will need is Builder's risk insurance to cover while you are rehabbing. 

Could somebody tell me how to estimate roughly about 10-15 mins for to know how much rehab cost would be cost?

The main thing is to address as many of the variables, UP FRONT, so that there are no surprises later.

It's a 5 bed 3 bath home that will need some rehab. 

Depending on the rehab estimate from contractors, we would determine if it makes sense to fix it up first or just sell as is.