If you want to sell Dota 2 items in 2021, there are a few ways that you can go about achieving this. The most obvious one is of course the official Steam-powered market that was created by Valve for this exact reason, however, the Valve marketplace is considered to not be ideal due to a few limitations it has. Those who want to sell Dota 2 items on the Steam-powered market can't convert their earnings into real-life cash and are therefore forced to buy other items on Steam instead, regardless of whether those are skins or video games. However, if you are interested in trading and are only looking to buy or trade Dota 2 skins, then the market powered by Steam may be your best option. It offers instant secure transactions without any additional fees and offers decent prices with many of the popular skins already available in stock. Keep in mind that if you are using the market powered by Steam, the prices may vary slightly, and you may not be always getting the best deal possible, still it is a decent option for any buyer.
The other alternative to the Steam market is a third party website such as the SkinCashier. These types of sites have become extremely popular within the gaming community and more often than not offer the best prices and have most of the popular skins in stock available for instant trading, buying, or selling. SkinCashier or any other similar website offers safe and secure service, customer support, and multiple different ways that you can use to turn your profit into tangible money. To use SkinCashier, all you need to do is connect your Steam account to it, and once the accounts are merged, you are free to use any service the website has to offer. There are numerous payment methods that are safe to use and you can get your cash to your preferred account. Keep in mind though that using some of these payment methods requires additional fees.