There are some popular sites that have a free section including Crunchyroll which does have a free option, 9anime and AnimeHeaven. They contain very large collections of anime in different categories such as; action, fantasy, romance and even daily life. For most of them, you get to listen to the podcast for free but come with advertisements or limited access to the premium episodes. Most importantly, always make sure the site is legal and secure enough to get rid of a nasty malware or get into trouble for infringing any copyright laws. That is why many anime lovers avoid using third-party websites because they are legal, safe, and help content producers.
Source: https://techbles.com/anime-websites/