@Netframed Of course a very cheap used card would go if you just want output something get yourself a gtx 760 or gtx 770. it's enough for output some kind of display and for surfing and watching videos. They go for about 10-40 $. So you could find something for you. But why would you want an rtx 3090 in combination with that board?
@Colif If you know how to search well and inform yourself, then getting a used card is pretty good. I've been using an used Gainward PHOENIX GTX 1080 GLS for about 4 years now with no problem it's pretty solid and runs like new. Quiet and powerful. Got it for about 250,- back in the days. And before i had a used ASUS ROG STRIX GTX 970 and this card is still used today in the Gaming-Rig of my younger sister. Not for long, because i will build her a new rig this year, including my gtx1080 because i did build a New rig for myself 5 days ago.