Ignorant noob with probably some silly questions, pls dont kill me.

Hi guys, ive been really intrigued with getting into electronics / programming.

I just have a few questions for arduino.

Is the arduino supposed to be part of the project? Meaning i will have to buy another arduino when creating a new project? For instance, if I want to make my own Audio DAC, does the arduino become part of the DAC or is it used just to program other chips?

Is the arduino old people friendly? I have done some html courses in college centuries ago, but that is all as far as coding goes.

Are the arduinos on sites like aliexpress ok to use? I see alot of them for sale for really cheap and I am tempted to try it...but I have no experience.

Thank you everyone.