There are a variety of different sizes. The most popular sizes are 15 inch, 17inch and 21 inch. Seventeen inch monitors would really be good for any kind of use. However, if you want to use your computer for design and some other applications were appearances are important, I would recommend a good 21 inch monitor. However, if your task is just to type the papers or surf the net, then even 15 inch monitor would be a good choice.
Printers are in the way similar to the monitors.
The best printers and most expensive printers available, are laser printers. However, if you are for example just typing up papers, then the quality of a printer is not that important. Some usage of the computer does not even require a printer, but it is always better to get one. The best choice are probably ink-jet printers, which are cheaper than the laser printers but still provide customers with great quality. Finally, let us look at some other devices that are not of great need for individuals, but you may chose to get them.