You have an option to buy website templates for as low as 25 bucks and customize it yourself with your text, links and pics before uploading to your domain/webhost. If it requires server side processing it might cost you a lot more.

properties/features/premium/

 Thanks sathi for your input.

Q. How to build a good website for free?
Ans. Plead/Beg a friend of yours who knows how to build the website for free.

 if you have no idea of coding, you can install wordpress, it has free tampletes. you can modify the contents and its easy to use. as you are going for business from online website, there are pople who can design your site for money. another option would be wix.com. its similar to wordpress but you have to pay them. they have beautiful flash sites.

So you want 'FREE' website right ?
Answer some questions first.

1. do you want the domain name (name of website) as ' <yourcompanyname>.com ' or are you happy with something like ' <yourcompanyname>.xy.xyz' .  If you are happy with second one (which i am sure you are not because you want to open business) then you can get domain name free at www.co.cc. But you will have co.cc at last of your website. 
If you want <yourcompanyname>.com , then you have to pay around $9-$10 per year. (You can get even this for free but only when you buy web hosting service.). So which option you want ?

2. If you think you your site does not require large disk space then you can get free web hosting for limited space at 000webhost.com. But they will not have many feature which you may need once your business grows. again their customer service is also not that good. So determine how much size you need.

3. After getting domain name and web hosting, use wordpress to make a website. There are a lot of tutorial about that . Wordpress.org

Conclusion->
"free domain name from co.cc ->free hosting from 000webhost.com ->installing wordpress ". In this way you can have free website ready. 

But since you want to have a website for good business plan , put some money and get paid version of domain name and hosting. Or, if you think everything is confusing, just pay me some buck and i will take care of everything because thats what i do.HAHA.

Anyway, all the best and let me know if you have any queries