Hardcore Gym > Home Gym > Commercial Gym
If you can get just 2 dedicated people to regularly train with you on your hard and heavy days, then you can pretty much make your home gym a hardcore gym.
Once you get a 300 pound Barbell Set and some extra 45s, you can start working out from home and build your gym from there.
Until you can afford a Squat Rack, you can just make Squat Stands like this. If you didn't already know, Lumber is very cheap. Think about it. A Barbell, some plates, and non-adjustable squat supports like these are all Olympic Weightlifters need to do the vast majority of their training with.
If you're concerned about safety before you buy a rack, then stick to front squats and platform deadlifts for legs.
Get something to do dips on and a pipe for chins and you're good.
Get a Dragging Sled and you've basically purchased every cable machine you can think of.