One of the many preparations you need to make while taking a road trip to Ladakh is keeping the cash handy. It is not one of your regular tourist destinations where you will come across an ATM at every corner. There was one instance when I went to Ladakh and we had to survive the entire route back until Srinagar on the cash that we withdrew from Manali. This was several years ago and at that time there were only two ATMs in Leh and both remained out of service during our four days stay and we had to budget our expenses on the cash we had in our pockets. Fortunately for us, we did plan in a way that we withdrew enough at Manali and the petrol pumps in Leh accepted the debit card else we would have been in serious trouble and would have had no choice but to stay in Leh until the ATMs were functional again. Here is a quick overview of Bank/ATM services in Ladakh region.
Manali Leh Highway: The last ATM on this road is in Manali and there is none until Leh so you got to carry cash. If you are planning to tank up fuel in Tandi, then you got to carry cash for that as well because they do not have the facilities to accept plastic there. Excluding the fuel charges, a two to three day travel from Manali to Leh can easily be managed in as little as Rs. 1000/head, depending on your expenses. There are decent enough and reasonably priced hotels in Keylong, tenting accommodations in Jispa and Pang so your budget per person can range anywhere from Rs. 1000 / head to whatever your wallet is capable of. Almost all major banks have branches in Manali but if you are travelling from Leh to Manali, then you will have to withdraw cash at Leh before you start your journey.
Leh: There are several Banks in the city of Leh now including SBI, PNB, Axis, HDFC and J&k Bank and they all have ATM facilities so it is almost impossible that you have difficulty getting cash in Leh like it happened in my case. There are however no ATMs in Nubra and towards Pangong and Tso Moriri so you will have to carry cash when you head towards these areas.
Srinagar Leh Highway: There are ATM services available in the town of Kargil. SBI, HDFC and J&K Bank have branches here but the only problem is of availability of cash in the ATMs. A safer bet is to withdraw cash at Srinagar or Leh, depending on which side you are travelling from, enough to last the entire route. Petrol pumps in Kargil do not accept credit or debit cards so you will have to pay up in cash.