counter module Ebay item number 181633676363
$10.88 for a eight digit counter with two ranges . One is 0.1 to 60 mhz and the other is 20 mhz to 2.4 Ghz.
And it can have the reading offset from the frequency so is is easily used to measure the local osc of a receiver and display the receiving frequency.
Another slightly cheaper counter has only 6 digits and will only measure up to 65 mhz. But should be more than adequate for many receivers.
Both modules are made by Sanjian Studio and more information can be found by searching on Sanjian Studio and watching Utube video's.
I have ordored one , but it will be a while before it is in hand.
Looking on Alibaba, it seems that a number of manufacturers use the modules in lab type frequency counters.