There are several reasons that an insurance policy can cost more or less at different agencies. Some of the more common reasons include the following:
a) Economies of scale - Larger agencies can often obtain better rates with most insurance companies.
b) Agent commission/fees are higher - Each agency makes their profit by adding a commission or fee on top of the real cost of the policy, profit margins will vary from agency to agency.
c) Deductible levels - Perhaps the policies appear to be identical in amounts of coverage, but one policy has a higher or lower deductible than the other.
d) Family or multiple policy discounts - If you have multiple policies with a specific agency, they may give you a rate discount for adding additional policies
e) Premium payment schedule differences - The schedule can differ as you can be paying monthly, semi-annually or annually.
f) Better personal rating from one company's underwriting staff - If your policy requires underwriting such as life or health, it's possible that certain insurers will view you as riskier than others, thus inflating the premium.
g) Agency specialty - Some agencies will specialize in one particular line of insurance such as health insurance. Because of the larger volume of business and insurance company loyalty, preferred rates will be given to clients of that agency.
Insurance policies can differ in price for any of the aforementioned reasons. When you're considering an insurance policy, it's best to research and find out exactly what you want to be included in the policy and which agency can get you the best price.
Also, take a look at Five Insurance Policies Everyone Should Have for a related reading.
This question was answered by Steven Merkel.