There are many variables. It depends on what you need them to do, how much information needs to be stored. An office with three employees needs a much smaller network computer than Google does. Price ranges $2,000 to $1M or more.
The OnQ Trio Home Network Kit costs about $160
The arrangement of computers in a network is known as Network topology.
A group of computers might form a network, but this is not necessarily the case. There is no commonly used collective noun for computers.
Servers
Two or more computers connected together create a computer network. Computers within a network can interchange data.
Not all - although most 'modern' computers do. Modern computers tend to be supplied with either an 'on-board' network adaptor or network card plugged into one of the slots on the motherboard. Older computers came without a network card, and needed additional hardware to connect to a network.
It is the relation between computers in network.
That is a printer that is accessible to computers in a network
That is a printer that is accessible to computers in a network
proxy or firewall
Not all - although most 'modern' computers do. Modern computers tend to be supplied with either an 'on-board' network adaptor or network card plugged into one of the slots on the motherboard. Older computers came without a network card, and needed additional hardware to connect to a network.
You can share a USB modem internet to other computers on the network by simply creating a wireless network with the comp where the modem is connected and then connecting the other computers to the network via the wireless network that you created.