A full set of tubes will cost a lot these days.
I have a basic tube tester, If you want, you could mail me all the tubes, I will find which ones are still good and which test bad. You only replace the bad ones.
You might have a diagram on the back of the unit (or find one online) where each tube goes.
If not, draw yourself a diagram of which tube type goes where, if you cannot read the number printed on the tube, put a piece of tape you can write on, and mark them so I test them and you can replace them.