Tubes or Radio Valves

There is a dire need for used parts in this world we live in.  Where can one buy an EL84 or 6BQ5 to finish your tube amplifier project?  Tube amplifiers are horrendously expensive but should this be the case? What happened to all the tube gear from years gone by.  Tubes apparently are now still been made in Russia and China. I believe they don’t carry a good reputation but is this really true?