We keep getting these sort of questions.
Its not negotiatable really people,in Europe for low power low speed radio comms you use 433 Mhz band,its licence free for transmission power under 10mW erp,which means that if you use 433 Mhz transmitter and reciever set at an erp of less than 10mW you will not end up being fined without having to go through type approval which is horribly expensive and long winded.Its the law and you can fight the law but you will lose in this case.The rest of the world its 2.3 Ghz again you can try to fight it but you will lose.
You will very quickly find yourself in court if you try to sell equipment which does not meet those requirements.
For that very reason several manufacuters make reciever/transmitter modules which can be found using youe favourite search engine.
I could sent you a schematic for a 433Mhz transmitter but you will need to have it emc tested anyway so by the time you have gone through all that youre better off buying a ready made module pair.