Mike H & Cranky,
I find taps & dies frequently at my local flea market, but the sellers think they're made of gold. It's seldom that I can pick up a tap or die for a reasonable price. I've never run across a large grouping of them either.
That said, over the last 10 years I have managed to assemble a working SAE tap & die set consisting of the most common sizes. I've also started working on a metric set, again working on the common sizes.
Just once I'd like to find a large lot like you found for $2