Recommendations for printing my own custom miniatures? Noob Q's

I'm looking for someone or some place that prints miniatures. I'd be supplying the file. I've never sent anything to 3d print and I must be awful at searching because I can't find a single site that has like a rough quote for minis. Of course I understand they would give me a different quote once I supply a file, but so far I have absolutely no clue on what to expect. $20? $150? Do you get a better deal if you print multiple items? Does it matter if they're different or all the same?

That, for starters. Next - what material should I be getting these prints on?

What resolution/parameters do I need to keep in mind for my files?

Does anyone have any recommendations for Australia?

Thanks