The act of creating anything original is Copyright in itself, but you need time and dated proof. The easiest and cheapest way is to send yourself a Sealed Registered Letter or package containing your concept or product. When it arrives, you put it away for the day you need to open it in front of a judge. If you wish, you can send it to a solicitor, your Bank to put in a deposit box or other notary.

The other way is to bring your product to market. The act of doing so tells everyone that it hit the street on 1st June, so when a copy comes out in a few months time, yours was first and half the population of the world is your witness. This is the option I take most of the time.