Congratulations on your becomming an installer!
FIRST RECOMMENDATION: One way and the surefire easy way is to simply ask for price quotes from other installers. That way you can get a general feel on what you shoud be charging in your particular area.
While there are some who may feel that this tactic is kinda deceptive, it is the only way you can get real marketing information on your competition. Having this information will determine whether you are charging too low or too high.
BEST RECOMMENDATION: It won’t be a bad idea to perhaps approach an installer in person and simply be upfront and honest and to ask for help (this way helps and is better than using deceptive tactics). I found out that most people generally love to share their knowledge and their expertise and you’ll find that they are more willing. If you are willing to listen and not sound like you are better than the other guy, you’ll definately get even more information that what you asked.
Additionally, you can check the CE Pro’s Magazine Archive for any information that may be helpful and use the Search tab under it.
Hopes this helps!
Seraphim