first come, first served

First come, first served.
The first people to arrive will be able to get the best choices

Something that you say which means that the people who ask for something first will be the ones who get it, when there is not enough for everyone

кто не успел, тот опоздал;
кто смел, тот и съел;
кто успел, тот и съел;

кто первым встал, того и тапочки (разг.)

Example: We've got ten cheap computers on offer. It's first come, first served. (thefreedictionary.com)

Related vocabulary:
[you snooze, you lose]