Good day

I know that this type of question has been asked many times before.

But is there any RELIABLE RS232 wireless communication modules available for under $20?
Or any RELIABLE communication modules that easily interface with a PIC?

I have played with wireless comms before, but it is not very reliable.
I only want to send 1 byte at a 20 meter distance and don't have a problem of sending it 5 times to make sure it has reached the other end.


Thank you very much!