Leggings fall into two distinct camps. Hosiery leggings are akin to footless tights and tend to be more affordable. The more expensive products are outerwear - cut and sewn clothing items made from thicker fabrics. These are more super-durable while being the height of fashion.
There are two different types of leggings: those made like hosiery (often the most affordable) and those made like outerwear from thicker fabrics, designed to be worn in place of pants. They're more expensive but cut-and-sewn and the most durable. Either way - they're a great fashion staple.