By Dan Weil The national average cost of auto insurance is $136 a month, but some brands can cost a lot more, according to Insurify. Many of us face a major financial annoyance twice a year: auto insurance. The national average cost of insuring your car is $136 a month, according to Insurify, an insurance-price-information website. There are several ways you can lower your costs, according to the Insurance Information Institute (III): · Shop around before choosing your coverage. Different insurance companies charge different rates. Experts recommend that you check at least three insurers befor…