Charging by the page is a bad, bad idea. What happens when a client realizes, "Hey, I can make what should be a 30 page site into one really, really long page for $99.95!"
Charge per project. Figure out how long (work hours) it'll take you to go from brief to launch and multiply by an hourly rate you feel is fair for your level of skill and your market.
Time x Rate = Quote
Same goes for a maintenance contract. How much time per month would you spend updating? If you say, $20/month for "periodic updates" - what if the client calls you every day and says, "Add a page" and this and that. Set strict limits on what qualifies as a "periodic update" - content? design? functionality?
Time/month x Rate = Monthly Maintenance Quote
Consult a lawyer for legal issues and contracts and consult a CPA for tax information.
And before you start a business in something be sure you have a solid portfolio together and get some experience and expertise under your belt.
Why do I say that? Because, I see plenty of things above that lead me to believe you don't really know what you're doing. First, your primary concern is "How much do I charge?" not "Am I using professional techniques and best practices that will best serve my clients' interests?"
Second, there's not a single mention of CSS, which should be the cornerstone of any web design company's skillset. Third is "java scripting" - Java and JavaScript are two totally different and unrelated languages.