It is very difficult to say that there is one company out there that is the "cheapest" in Pennsylvania. There are companies that have better rates than others but a lot of premium rates have to do with the amount of coverage desired, the age and location of the applicant, and individual standards by insurance companies.
My best advice to you would be to contact an Independent Agent, like myself. Independent Agents have the ability to quote your renter's insurance with several different companies in order to find you the best rate that fits your needs. If you go to an AllState agent, or an Erie agent - you will only get a quote from what that company can offer. These are called Captive Agents and their resources are very limited.
Broker, Mooney Insurance Brokers, Philadelphia, PA
Have you seen that esurance TV commercial (http://www.youtube.com/watch?v=lN5Wa8IqIdo) ? Everybody wants CHEAP insurance and almost any insurance can give you CHEAP insurance .... But the reality is that you get what you pay for. Renters insurance is probably the most affordable coverage that you can find and will probably cost you $15/ month for great coverage. Make sure your policy has replacement cost on contents and includes additional living expenses. Saving $5/ month could wind up costing you thousands of dollars if you have the wrong policy. Check with an independent insurance agent who can look at multiple carriers and see what policy is right for you.
My best advice to you would be to contact an Independent Agent, like myself. Independent Agents have the ability to quote your renter's insurance with several different companies in order to find you the best rate that fits your needs. If you go to an AllState agent, or an Erie agent - you will only get a quote from what that company can offer. These are called Captive Agents and their resources are very limited.