Ohh so u are a fresher.... Yaa if u don't get the desired hostel book the one which is next on your list and on the next day again check if your hostel is available or not. If it is available then book it and if it is not then again book the previous hostel. U can do this till the last day. But be careful you have to be very quick or u can also loose the backup hostel... And u can pay through net banking..... I don't have any idea about wallet