Maximum you need is a couple of dumbells and a long bar, although you could probably get a couple of kettlebells (and a book about them) for under a hundred quid. A punchbag is good craic too.
The key is to mix up what you are doing to avoid boredom, and to read up a bit on different types of training session and exercises involved.
In comparison training on a multigym would actually be more boring. A variety of exercises with free weights, maintaining good posture, will give you far better gains in terms of shape and functional strength.
If you get easily bored stick some music on and work it into a circuit split between upper and lower body.