I believe the most important consideration is whether you can maintain the pace of your training uninterrupted by financial constraint. When you have the money, pay cash as you go. If cash is tight, borrow, either by credit card, a lender like Pilot Finance, or friends and relatives. Flying skills atrophy very quickly and unlike most athletic skills, the loss of flying proficiency is deadly. So whatever financial measures it takes to maintain the cadence of your training, do it and just keep moving forward.