1$ DIY pickup

1$ pickup to make yourself!
Many have tried to make a magic golden sound from lesser materials.
Sadly, the *magic*  was only present in the sales hype, paid endorsements and glossy advertising necessary to sell an inferior sound device, financed by the profits of selling a 50 cent part for hundreds of $$ in retail, adding the necessary signal preamp-enhancer-processors on top of that.

Piezo speaker from a musical greeting card.

A 10Cent do-it-your-self piezoo is priced just right. Free is more right. More is too much.
Really, with a little bit of luck, it IS free. Dig up the silly tune musical greeting card, or the bust electronic mini alarm clock, the bust ghetto blaster with treble piezo speakers, or any crappy electronic device with a sound output, like your kid brothers hateful toy with a siren sound – the piezo´s make the beeping sound every where in cheap electronic devices. Inside, find the disc shaped “speaker” part – it is usually a circular brass sheet with a silver metallised ceramic plate on one side. Be careful you don´t bend it, the ceramic part breaks easily.
If you are not familiar with a soldering iron, have a friend help you go on to the next step. Use only resin core electronic solder wire.
Get a thin screened wire (a center wire and a copper mesh screen wrapping), again from a scrap piece of electronic equipment, strip the outer insulation, twist and bend to one side and pre-tin the screen wrap, and cut it very short. Pre-tin the center wire, an have the insulation protrude just 1/8″ or 3mm from the screen wrap, and then a bare, tinned 2mm inner core.

Soldering a screen wrap wire to the piezo element.

Carefully solder the screen wrap wire to the brass foil backing´s edge – make sure it can not touch the ceramic part. Then, carefully, using very little solder, very little heat, and be damn quick!  solder the center wire to the silver metallized top part of the ceramic disc surface near the edge. If you linger or apply too much the piezoo silver top will come off. Try again in another place.
You have now made your very own piezo disc pickup, to further improve it, you can insulate it with epoxy for durability, and sandwich an insulating sheet of plastic tape between the ceramic part and a thin metal foil screen on top, to screen against hum. Attach a jack plug to the far wire end, connect it to an amplifier. You have now made your very own piezo disc pickup. Try fitting it to different places on your instrument. It will make sound! Don´t expect it to sound any better – or much worse – than a 100$ piezoo.
Then, look for perfection. That´s a bit harder. Have fun, do play music. That is my best  more advice about piezoo´s.