Your making a mountain out of a mole hill trying to save a dollar......(A) Never remove the crystal (xtal) from a Transmitter (not controller) it is as the rest are saying illegal to change as you need a certified oscilloscope technician to tune the xtal,,,(B) If you have a receiver (Rx) then all you need to do it look on the back of the Tx (Radio/Transmitter) and it will tell you what channel you need from 15-41-58 whatever single number is back there,(I am on channel 41) get THAT brand of Rx and order a crystal for that number they are anywhere from $3 to $19 depending on the brand.......you do not want to mix brands unless your plane is a parkflyer...go to tower hobbies, under futaba (I assume you have an FM radio) and order the xtal for the number on your radio, sounds like your hobby shop isnt the best , but they wont carry a whole line of xtals and they'll have to order it anyway.........you dig?....while your online see what else you need to order, fuel line,extra glow plug,plug wrench, tools....all manner of things....what plane is it you have?...glow ,electric...it will make a difference in the price, you can get a Rx/Xtal for $18 for a parkflyer.....Rog
To recap, you dont send a radio off to match a rx you buy a new xtal for the rx, that simple..