Summarize:

The jock strap is the most common supporter for a cup. It has a pouch for the cup and 2 elastic bands that wrap around your legs. Jock straps usually come in small, medium, and large, and they're extremely elastic. Select a jock strap that will fit firmly around your waist. The waist size ranges will be listed on the packaging. Jock straps tend to be cheaper than compression shorts. Don't use a jock strap that doesn't hug your waist firmly. You don't want it falling down as you're running. If you're getting a cup for hockey, get a hockey jock. It's a special type of jock strap designed to fit into hockey pants. Jock straps are great choices for sports where you run or turn a lot because they don't tend to fall down. Almost every kind of player can wear a jock strap, including baseball, basketball, rugby, lacrosse, and football players. They tend to be a little uncomfortable if you're sitting down a lot though. Compression shorts are a good alternative if you don't like jock straps. Compression shorts are basically tight-fitting boxer briefs with a slot for a protective cup in the front. Get a pair of compression shorts that list your waistline's measurement on the packaging. They should hug your thighs and waist firmly, but shouldn't be so tight that they cut off circulation. If you have sensitive skin in your inner thighs, opt for compression shortsthey feel like tight boxer shorts and are less likely to cause chafing. Compression shorts are great for sports that involve a lot of running, like basketball, baseball, or football. They're also excellent for biking. They may fall down if you twist and turn a lot though depending on the shape of your body. Impact shorts are like compression shorts, except they have foam padding around the thighs, tailbone, and sides to soften any blows or falls. They're popular amongst snowboarders and skaters because they keep bad falls from seriously damaging your hips or legs. Select impact shorts if you won't have any padding around your hips and thighs and need some additional support. Impact shorts are often called padded shorts or snowboarder shorts. Impact shorts are great for snowboarding, rugby, skating, or boxing, but they're not great for sports that already have padded uniforms, like football. You also may not like the way they feel if you have to run a lot, which makes them poor choices for sports like baseball or basketball.
Get a jock strap for a basic setup. Opt for compression shorts if you don't like the feeling of the elastic bands. Select impact shorts if you want some additional protection.