I bought an $8 1"x24tpi die on ebay last month, used it to extend the threads on a steer tube yesterday, and am fairly sure I destroyed the fork's usability. It removed way too much material. I've never had that problem with the Park die. Can't comment on a $25 die, but don't get an $8 die.

The pitch on a standard fork is 24 threads per inch. This is a fairly fine pitch. The standard pitches for a 1" diameter are 8tpi (UNC-unified national coarse) and 12tpi (UNF-unified national fine). Bicycle forks use finer threads than the UN standard, probably because coarser threads are deeper, and would require thicker material.