Every SME (small and medium enterprise) has its own requirement of connecting to the internet depending upon several factors. Budget and utilization are the biggest factors. You can identify an option from the list below to find out which Internet Connection Method best fits your current organization structure.

1. Single computer/server connected to the Internet directly and other computers connect through this computer only. It's a simple ICS (Internet connection sharing) scenario where one computer is connected directly to the internet using a PPPOE (Point to Point over Ethernet) connection which is a base of Today's broadband connection. It has two interfaces, one connected to the broadband modem and the other one connected to the Hub or Switch. Other computer on the hub or switch can now point to this one computer to access the internet. Any communication to and from the internet will have to pass through this one server/computer. For any reason if this computer is down or offline, all remaining connection to internet will break instantly.
2. You can use a residential gateway or through another computer on my network to connect to the internet: This gateway is kind of a device persistently connected to the internet and all other computer on the network will point to this device in order to go out on the internet. There is still another way to connect is through various popular software's commonly known as PROXY which will be installed on that machine which is directly connected to Internet. In this case, all computers (Internet Explorer) are pointed to that PROXY for internet access. Typically, a DSL or cable modem is connected to either the gateway or the PROXY server, which intern is connected to the Ethernet hub or switch.
3. A computer plugged into Hub or switch is directly connected to the internet: In this case all the computers are connected on to a switch and needs no gateway or ICS to access the internet. This is kind of risky scenario as all the computers will be open to virus and intrusion like threats. I would personally suggest never go for this solution as security is something missing at all the times. Instead go for either the 1^st or 2^nd solution which keeps the security on the network from any outside interference. A computer running Windows XP with ICS enabled is the best living example today.
4. Single computer accessing the internet by a direct dial facility: Only single computer is counted in this scenario with some kind of dial-on-demand application interface to enable the internet connection manually whenever there is requirement. Home user is the best example in this case. This means at any point in time if a requirement of expansion is noticed, step 1 and 2 can be accomplished easily and quickly.
5. Computer belongs to a network with no internet connection: applicable incase 2 or more computer are connected over kind of phone line (HPNS - Home phone line network adapter) or in a workgroup using Ethernet hub or in wireless ad-hoc mode.

Therefore, now you know which type of connection to go for and save up some on yourself.