If it's about cost forget metal printing, also forget about the expensive machines and service contracts. I'm not saying those are not worth it, but if money is an issue, they are no option.

The usual way is to make a model for investment casting.
The wax used in the normal process is replaced by a resin that's burns out without any ash - that's the plan.
If you don't have the equipment for investment casting, you will have to buy it (more money and as important more stuff to learn) or find somebody who will cast it for you. Make sure the someone has experience with using resin, it will save time and headaches.
There are many resins available that claim to be castable, but there seem to be large differences, it's worth checking whether the printer - resin combination you choose has a good track record for being used to create models for casting.
I assume the best bet is the B9Creator and probably the DWS printers. Both see jewelers as their main or at least an important customer group - there might be a phletora of others I don't know about.
There are many other printers with different user interests like the Form, Titan, Pegasus, CTC etc.. The may be cheaper or fancier or greener, but if you have a problem with jewelry and casting this will not be much help. Also you might have to find the best resin for casting and the operating parameters for it yourself.
I can't say about DWS - because I haven't found their forum - , but the B9Creator forum has a lot of people offering help not only for the print process, but also for the casting.
Always a good idea is to look for manufacturers forums. Keep in mind that people usually go there to complain. So a printer is usually not as bad as it sounds. Importantly you can see whether the people get helped and if the stuff they do is the stuff you plan to do.
The companies with the expensive machines often claim that "professionals" have no time to visit forums, so they don't have any. In this case you will be dependent on the knowledge of customer service.
But I'm a simple man, so if somebody doesn't have an accessible forum, I always think about what they've got to hide - the modern professional uses forums to gain knowledge too.

Depending on the number of pieces you plan to do, having the models printed in metal or castable resin at shapeways or any other service might be more cost effective and might have a learning curve not as steep.