I think it can be worth it if you use it a lot as the more you use it, the more your savings add up.
But even though directly copying off the shelf products to print is often cheaper than buying the product, the real money saved is in custom items.
I've printed a lot of smaller things for a few cents that would usually cost a dollar or two each (such as cookie cutters for the wife) so over time those small things can save heaps of money. Then there are bigger custom things like my reef-pi power board which is a few hundred dollars cheaper than any other controlable power board I could buy (but at the same time it also required way more work than just printing a box). It is definitely more of a "hobby" item though than something you buy specifically to save money, IMO the money I've saved is just a bonus :)
I look at it like the marine fish hobby, if you want to be successful you must consider 3 things.
1) cheap
2) quality (without tweaking)
3) easy / no need to invest time
But you can only pick 2 :p
IMO I've gotten my $200 printer (my first one) to have excellent results, but the prints weren't amazing quality straight away, lots of stuff broke along the way and it took a lot of time, testing and adjusting (fun in my eyes) to get right. Or I could have spent 5x as much and gotten the same results without investing the time.
I don't think first timers need to buy an expensive machine, but they do need to realise that its a whole hobby on its own with a steep learning curve, even with an expensive machine (although it is doable by everyone if they invest the time). I actually think there is a lot more benefit to buying a kit (even a moderately priced one) as even prusas break and knowing what went wrong and knowing how to fix them is invaluable.
But if you have the money then spend up big, I know I would :p (if you have the money and want to learn a prusa kit is probably the best option)
