For starting blog to help CA students, the best way is to setup your account either on Blogger or Wordpress. I have started from Blogger, but now I think Wordpress is little better than Blogger. Wordpress has more features and tools in comparison to Blogger. You will get free hosting in Wordpress and Blogger to upload your posts online. However, if you wish to make your site viral over Google Search results, then better you buy domain for your site. If you wish to purchase for Indian users only, then better you purchase .in domain which would cost you nearly Rs.170 for the first year and later on Rs.500 per year.
"Time & Tides waits for none"