Nopo About 27 accounts (26.666)
I’ll say this,
You need free MEGA account but want 400GB of space? Since you are preparing for IIT you may as well go all out. I hope this is for serious academic purposes so buy an annual plan. And if you planned to buy, buy it from the android app through google play credit (not credit card) that will be much cheaper in Indian currency.
Keep an excel file with password encryption and keep track of different free MEGA accounts on that. You could also mark each account within excel sheet as to what kind of materials are there or will be there in any particular accounts.
Remember to login to each accounts every year or it will get terminated due to inactiveness.
I was one of those lucky people who were smart enough to not take these free storage for granted before MEGA went from 50GB to 15GB and since then I have around 865 50GB free MEGA accounts on me for keeping backups and other work stuffs and also sold a few.
Though nowadays if you create a new account at first you will get 50GB for few months but it will drop down to 15GB then you have to rearrange the excess 35GB on one or more accounts also there a time limit within which you must adjust the storage space below 15GB or else after the limit is over you won’t be able to delete nor download or move to anywhere unless you pay for any monthly plan I learnt this the hard way and within 30 days they will eradicate all the files in your drive . So plan strategically and think a little… no seriously…think a little. Don’t get too comfortable with free storage.