Is it worth getting into mining nowadays?

I've been checking out some smaller mining machines and rigs that don't cost a lot of money, so I've wondered for a while now, is it worth getting into mining or is it best to just buy and resell? Is it better to buy a whole mining machine(they look like mini servers) or is it better to source the different parts separately and build a rig myself? If getting into it with some small machine for starters is worth it, what would I need specifically in order to start operating and is there any difference in which coin I decide to mine for(for example BTC, ETH)? Any advices are appreciated.