New how do?

Hello I am new to magic but have had some fun games playing commander with friends. I was wondering how best to get started? There's a lot to take in so I don't know much about deck building or even how you would get cards for cheap(I know you can proxy, but I want to see if official options are reasonable). If anyone has any other advice for a beginner feel free to let me know.

Ps. Thanks in advance for whatever wisdom I obtain from this.