Sixty years ago this month, the August 1965 issue of Radio-TV Experimenter carried the plans for this three-transistor shortwave regenerative receiver. The parts would set you back only $14, and the completed set was said to be the size of a QSL card.  As shown here, it covered 4-15 MHz, although it could be modified to cover any range between 500 kHz and 30 MHz.  Even a beginner could have it together in about 8 hours.

The set called for a 50 foot antenna and high impedance headphones, although on strong signals, a speaker could be used, in conjunction with a matching transformer.