yes it is possible to print in metal; It's done with big machines that use metal powder, lasers and SLS (Selective Laser Sintering).
What is your budget?
These machines are expensive and not for home use :-)
For smaller projects, you can use 3D printing services like Shapeways.
At shapeways (and probably the others) they have a materials page with a design-guideline for each.
Depending on the method the metal prints get infused/coated with other metals later on (such as gold).
As they get baked/heated moving parts and fine details are a problem.
SILVER has finer possible details I reckon, see http://www.shapeways.com/materials/silver
...still over 0.5mm though.
Another method is lost PLA/ABS casting for example.
You print a cheap plastic model until your happy with it, put it in a sand form and poor molten metal into it. The plastic will melt away, leaving a "metal copy";
Check out http://3dtopo.com/lostPLA/
Regarding your models with the info you give, it's most likely going to be a bit problematic. I make earrings and looked into getting them printed in metal, but the process requires a relatively thick minimum-wall-thickness, while plastic printers can print 0.7mm and less.
If you can, please share images of your model, so it's easier to make a recommendation.
0.5mm is rather thin and would require a FDM/FFF printer with a fine extruder nozzle, a light-curing-resin/SL printer, or a SLS plastic machine but companies usually don't accept models with very thin parts to avoid problems.
If it is an option, you could still color your plastic models with metal-like lacquer, that's how I do it.
Even if you insist on creating it in metal, it would be a good idea to get a cheap plastic printer to print prototypes, as it is a lot cheaper.
1 cubic centimeter of ABS-filament (roughly equaling 1 gram) costs about 0.02-0.06€ (0.03-0.09$).
They do make silver and gold PLA by the way, but it's not looking like real metal at all, still pretty neat.
Shapeways charges 8 Dollars/cm³ for metal printing, and 20 Dollars/cm³ for silver. There's quite a setup fee per model though, take it into your considerations.
About plastic printers for prototyping
I own two printers, a UP+ from PP3DP and a Printrbot LC.
If you want something with relatively high detail, capable of printing complex models with rather easy removable support structure, consider an UP (899$ for the mini, 1600$ or something for the Plus). It's closed source so it limits the things you can set, but it works like no other printer I have seen. Some companies advertise with finer layer heights, but that's only one side of the coin.
If you are a tinkerer, go with a reprap based machine. Machines prices have come down a lot (from about $400), you can print with multiple printheads (costs about twice to three times as much) and use soluble support structure instead of break-away, and the open source software is getting better and better. Though you really have to learn and work with both hard- and software to get good results.
If you want the highest details, consider a resin printer. It cures resin with light (UV, visible, depending on the method and resin).
There are promising entry level machines which have been announced or crowd-funded, such as the B9Creator, Form1, and OpenSL.