Doing it normally on the actual site would be annoying though because of the way it's set up, so there are some tools to help make it faster and easier, like here https://mpcfill.com/guide. It's not like cheap cheap but I don't need new decks super often and it's nice to be able to use some cards I otherwise wouldn't be able to in my decks.
MakePlayingCards.com
Doing it normally on the actual site would be annoying though because of the way it's set up, so there are some tools to help make it faster and easier, like here https://mpcfill.com/guide. It's not like cheap cheap but I don't need new decks super often and it's nice to be able to use some cards I otherwise wouldn't be able to in my decks.