how a patent can save some ones idea ?

Question

what if some one have a patent from 1 country but someone from another country copies his idea

what is the cost of patents registration and where

Answer 1

(1) Generally, the patent will only cover infringement in the country that the patent is issued in. Now, the second guy can't get his own patent (because he copied someone else and his invention is not "novel") but, unless or until the original inventor patents his idea in the second country, he can copy it. (Note, the copier probably CANNOT import the copied products into the original inventor's home country if the original inventor secured a patent there).
(2) It really, really depends, because the patent process can be long and drawn out. Actually drafting the application can cost thousands of dollars if the patent is complex. Then, if the patent examiners reject the patent, you can spend thousands fighting their rejections. Once you secure a patent in one country, however, it is usually easier to get patents in other countries, provided you meet that other country's statutory requirements. But you usually have to file for the patent right away, because continued use of the invention without a patent may bar you from getting a foreign patent.

(3) See a patent attorney working in your jurisdiction. They can answer all of these questions and provide you with good estimates for prosecution costs. Call your local bar association and ask for a referral for an attorney registered to practice before the US Patent and Trademark Office. Since patent attorneys are also specialized, tell them the nature of your invention (mechanical, electrical, plant, chemical, computer, etc.)

Answer 2

There are international treaties that cover that sort of thing. Unfortunately, depending on what country that person is in, you may just be screwed.