3D printing what to get???

I have been frustrated at not finding old parts I need, or they are very costly as they are hard to get....
So I am thinking Of saving for a 3d printer but.....I have no idea of the good ,the bad and the just plain useless.
The Questions I have are.

1, what would be a good printer for me would need to be lower price range,and what are the running costs

2, have any of you brought from China?

3, how easy hard are they to program /run

4, would it pay for itself in the long run, not thinking of selling bits made, just saving on buying bits

5 what should I avoid at all costs

6, is a used printer an option? and if so what should I check on printer before buying.

7, are there places to D/load slot car stuff printer ready.

8, any other tips advice you can give me please,


thanks
Graham