If you are looking to get some Physical Comicbooks then try some local shop. And if you wanna buy them online then visit: https://www.mycomicshop.com/ its a great place. And if you want a digital copy then there are lots of website. Google them 🙂

Marvel unlimited or marvel comics
Both of them are official apps

In their official comic apps you can

You should look for the e books because the physical ones are way expensive