Building useful things yourself is very satisfying and can be quite inexpensive, compared to buying a device.  You might be surprised at what can be found in other people’s trash.
In various places, I have found a good, working Drake TR4, a museum-appearance Heath SB-1000 linear amp (but with a broken meter switch and a weak 3-500Z), a nicely built but inoperative regenerative receiver, an excellent oscilloscope and many other electronic gadgets that provided a large amount of parts.
Some construction information and articles are found below.  Some are .pdf’s which will display immediately and some are Word documents to download, then open.
Also, look at the Resources page as there is some crossover between “Resources” and “Construction”.