The necessity of renter's insurance should be considered when moving into a new apartment. Before purchasing renter's insurance, dependent students should first contact their parents' insurance company. Several insurance companies have their policies set up so that dependent students can be covered under their parents' homeowner's or renter's policies while they are in school.
However, independent and married students are most likely not covered under anyone else's policy and should seriously consider purchasing their own renter's insurance. The cost of the policy will depend on the amount of liability coverage, the deductible that you choose, and the type of building in which you live.
Actual quotes on costs can be obtained from independent insurance agents who must sell you a policy. Agents are listed in the yellow pages under "insurance." Shop around for a good price before buying a policy because prices may vary from company to company.