I will also jump on the wagon here and agree that machines are a waste of time.
Free weights is the only way.. For a starting point, a barbell and weight plates is all you need.
Also, consider this.
Get a used Beer Keg or a few, and fill them with different amounts of water. 10kg, 20kg and so on. Even at a light weight they are hard to handle (splashing water). They will work true strength, stabilizers, core etc.
Just a few exercises you can do with a keg:
Squat, bent over row, Press off floor (or bench press), lunges, press over head, pick up off floor (deadlift style or between legs), walk with keg pressed over head etc etc.
The reps and sets can only be determined with the outcome you desire.
Sandbags and kettlebells are also cheap, fun and a good starting point.
Point of Fact here:
Old time strongman were and still are stronger then current day weightlifters even with all the technical machines, equipment and drugs.
Think about what they were eating and lifting in those days, and that is your answer.
I also fixed my chronic back problem of 3 years by lifting freeweights
exactly what all the specialists told me not to do