An essential of regular wear, men's underwear helps with sweat absorption and reducing chances of crotch rot. With some basic types, which you chose depends on what you find more comfortable. Available at varied price points depending on the brand you choose.
The modern underwear
The modern men's underwear we know was developed in the 1930s. The first one was with a 'Y-shaped' fly called 'jockey' was sold at the Marshall Field's store in Chicago, designed by a company called Coopers Inc. These were such a hit that in the first 3 months 30,000 pairs were sold. The 'jockey' name was chosen as before that point only the jockstrap worn by jockey's while racing provided similar support. Later the company was restructured due to the Great Depression and was also renamed Jockey - the famous brand we all know today.
Basic types of underwear for men
The original is the 'brief', commonly in white but also available in many colours and patterns. The 'boxer-brief' is kind of like shorts but tighter and fit the form of the wearer, made from elasticised cotton similar to briefs. 'Boxers' or 'boxer-shorts' are made from cotton and are not elasticised, also called boxers cause they are similar to the shorts worn by boxers in the ring. Boxers generally have buttons on the fly.
Underwear also comes in other materials such as polyester mixes, which you like is a matter of personal preference. Generally, cotton-based materials are recommended, unless one is built for specific activities like sports using another material.
Why wear underwear
The first thing about underwear is that it has to be clean, ahead of which it is beneficial. It helps absorb sweat well unlike pants and jeans. Men's underwear also helps avoid abrasions due to friction. Underwear also reduces chances of crotch rot if you keep them dry.
Underwear should be changed daily and should not be worn to bed as the body needs to breathe and be free while asleep. Available at many different prices depending on the brand and material. A lot of brands also sell packs of 3 or 5, these can cost a little less comparatively.