The cost is not fixed. And different for different branches. I think the starting price to secure a seat in B.Tech is 5 lac. I will suggest you not to contact any agencies. And directly go and talk to the admission department (Koel Campus). They will properly guide you if you really want to take admission in KIIT.
If you are going to take admission in KIIT through management quota, the total expenses will be around 25 lac for 4 years.
Hope this helps. Thanks.