Appropriate Method for finding out Arm's Length price u/s 92 of IT Act.

There are five methods mentioned in the IT Act to prove the Arm's Length price. But also the method to be adopted changes from case to case. I have a newly started manufacturing enterprise which has made a purchase with associated enterprises. But there is no uncontrolled transaction to compare with it. And the company also has incurred loss in the previous year. Which method would be best to ascertain arm's length price for purchase? And how to proceed about it?