Many countries need no visas at all. Other countries issue their "visas" on arrival at the airport or place of entry. Turkey, Cambodia, Egypt, Zambia, and South Africa are examples. Other countries require them done in advance but very easy and can be done on the interent for example Australia. The countries that require visa in advance such as Brazil, India, China and Russia are usually the most expensive and complicated.

South Africa I believe is unique in the requirement of two adjoining empty pages and they are VERY serious about that requirement.