I want to get a modem in which I can insert sim of any network provider and access internet. Is data card is good for this. if not suggest the best thing other than mobile phone as Modem.

Now almost all datacard comes unlocked. Almost all provider provide card either from Huawei or Micromax . So won't matter which one you buy, just look for cheapest and which support atleast 7.2 mbps speed. Though data card through BSNL comes unlocked.

so do you want to say that I can use any sim on the BSNL data card .
Also tell the various costs of data cards or weblink for the same

Ya, I can confirm as I had used Micromax from BSNL, worked on all SIM . Also a person I know had used another Micromax from idea on TATA Docomo.

I exactly don't remember but 7.2 mbps version from BSNL costs Rs. 2.5K and 3.1 mbps cost Rs. 1.9K

Likewise, idea netsetter cost around Rs. 1.5k