Even a BITSIAN cannot answer this question because unlike other colleges the fees structure in BITS is not fixed and can increase upto 15% every year(on tuition fees).But you may approximately take it to be 20 lac. I know it is a lot but I would like to add one thing getting a loan is very easy for BITS CSE ( basically for any branch) and if you have financial problems than you should get some info about Merit Cum Need scholarship of BITS given to almost 20% students every year.
Hope this was of some help..