Most webmasters started off using single domain hosting or shared web-hosting services. Shared web hosting means you share a server with dozens of other webmasters. Typically, shared web hosting plans allows you to have more than 1 domain per shared web hosting account with a predetermined hard disk space and bandwidth. The cost is usually pretty low. You only need to pay around 3-10 dollars per month.
Although it is cheap to host your website on single or shared web hosting accounts, there are many disadvantages you should be aware of.
By the nature of shared hosting, the server resources are shared among many websites, therefore it is very easy for resources such as CPU and memory to be used up quickly. Certain types of websites such as proxy sites are known to generate high CPU utilization, therefore if your website is on the same server, be advised there is a possibility of your website going down. Spam complaints against other sites on the same server will also affect your website. Any form of denial of service attack against someone else hosting can impact on the uptime of your website.
Also some web hosting companies over packed too many hosting...