Hi Jyoti, it is really a good to have a rank in Top 100 in any exam it's a really a matter to feel proud on yourself. Coming on that will you get a free seat in ANUPGCET is somehow not possible. See it is sure that you can get any seat through your good rank with scoholarship also but taking any free seat is not possible but you can get some amount of Fee Waiver from the University that's it only these you can get with the rank you have got.

Good Luck.