Your business will require that many things are taken care of beyond directly generating revenue.  These include managing your cash flow and payroll, and keeping your expenses paid such as web hosting, domain name registrations, and taxes. You'll need to design a website or pay somebody to do that, and you'll need to manage a good marketing strategy. 

Website Expenses

Designing and maintaining your website comes with a cost in either time or money. You can get something up and running quickly and inexpensively by using proven open source software such as Drupal or Wordpress.  With both, there are many prebuilt themes to choose from which will allow you to customize your website in many ways. As your site grows, you can continue to spend time and money to enhance it.  This can be a slow and steady process as you learn more about what your audience wants and needs.  At a bare minimum, you'll want to add a new page of content once per week.  This gives people a reason to return, and will help generate some buzz about your website.

You'll need to pay for web hosting.  There are free sites out there, but they are very limited and often display intrusive ads that will detract from the user's experience.  If you start out with a Drupal or Wordpress site, you can get everything you need at a shared hosting company.  These tend to run less than $10/month, and will be more than sufficient until your site is getting a lot of traffic.  Once you reach the point where you either need a feature that the shared hosting provider doesn't support, or you're starting to reach their limits in either bandwidth or cpu usage, then the next step is to move to a dedicated or cloud hosting environment.  This is a big step because it means that you'll either need to learn how to manage a webserver or pay somebody to do this.  Dedicated and cloud hosting starts at about $100-$150/month plus the payroll involved to manage it. 

You'll also need to register at least one domain name for your website.  This is relatively cheap, and you can get a domain name for less than $10/year.  A common strategy is to have several  smaller niched websites, so each one will need its own domain name.

Payroll Expenses

Payroll is completely subjective to what you're trying to do.  If you're creating an informational ad driven website, payroll consists of paying somebody to write content for your site.  Of course, you can write content for your website yourself, so the expense is really either time or money.  If you're running an E-commerce website, then you'll need somebody to fulfill the orders and handle customer service issues.  Both of these things can be outsourced to a fulfillment company for a fee.  Promoting your website is a must if you intend to get enough traffic to pay the bills, and this tends to be the biggest draw in resources for an online business.

Taxes

Consult your tax advisor for tax related inquiries. Some things to keep in mind are when you need to charge sales tax, what payroll taxes you need to worry about, state and federal income taxes, etc.

Entity Formation

You'll need to register your business, and there are several types of business structures to consider.  S-Corps and LLCs are often the best in terms of taxes and legal protection for small businesses, and each has their benefits and drawbacks.  Before you choose, be sure to seek legal and tax counsel.  Every situation is different, so it's best to get it done right.  The state in which your business is set up in is another important factor.  Different states have different laws and tax rates.  Nevada and Wyoming are good states to consider.  Again, every situation is different and it's best to have somebody that knows the fine points take a look for you.

Next Step

At this point, we've scraped the surface on the several topics involved in getting started with an online business.  We've talked about figuring our your website's topic, how you plan to earn money from your website, different methods to market the website, and some things to think about regarding the business side of your online business.  If you've missed any of these articles, please take a look at the links on the left of the page. 

Now it's time to jump in and get started by reading about why it's important to generate buzz about your website.