Lets face it, this is probably not going to happen. Sports cars are expensive to buy, to run and to insure. However, you can keep your premiums down if you take a few common sense measures.
Getting your insurance online is probably the easiest way to start saving. Companies offer discounts to people who purchase their insurance online, and it is very convenient for the purchaser as well. You can compare between policies quite easily on the Internet, and also receive quotes far more quickly than through the post.
Lower end or more common sports cars can often be insured for less, and are cheaper to buy so you win twice there. Once you have your car however, take the necessary security precautions to keep it safe. An annoying car alarm is an excellent investment, as well as imobilizers and a steering lock. Parking in a secure garage is also another way to assuage your insurers fears and persuade them to lower the premiums.
It's not only for their benefit either. If your car is stolen then you will face an increase in premiums, so its in your best interests to keep it safe.
Otherwise, saving money on sports cars works in much the same way as saving money on any form of car insurance, be a good driver and keep a clean record. Insurance companies love clean records and will reward you with lower costs. Keeping the teenagers out of the drivers seat is always a good idea, you wouldn't want them behind the wheel of your powerful beast anyhow, given that they are already four times more likely than adults to wrap the car around another object.
Combining your insurance over another car can help too, as well as combining it with house and contents insurance. The more business you send their way, the more likely they are to offer discounts.
Finding a good insurer may take a little bit of time, but it will pay off in the end, and surely you and your car deserve that.