This might work in R/B/Y, but I know it works on FRLG. Don't hold your breath.
Remember that Nugget bridge, back on Cerulean City? The Rocket Grunt up there gives you a Nugget before he battles you. If you lose, he'll give you another one when you fight him again. Take a Magikarp or something and keep losing to that trainer. And don't worry, the amount you lose usually won't be above the cost of selling the nugget.
Signature credit goes to .Impact.
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