inlayed Mexican loop sheath requires at least one tool, a VERY fine stitch marking wheel, that Chuck says must be found used on eBay or some other source because they are not being made anymore
With all due respect to Joe but three things in error with that statement.....
1) The Mexican loop sheath is not inlayed it is carved - I show how to do the snake skin inlay on a pouch sheath, but the basic process can be used on any sheath........
2) The fine over stitch wheel is not required - it's nice, but a common 7 or even 6 SPI wheel will work just fine - in fact for some one just beginning or even at the intermediate I'd recommend the 7 SPI with three cord linen thread and #1 size harness needles.
3) Fine overstitch wheels are available elsewhere than EBay and are still being made. McMillen Tools for instance makes/sells them up to 12SPI IIRC, Bob Douglas sells older ones in various sizes (and lots of other fine tools), and there are other sources. The other option is to use a fine stitch pricking marker such as made by Dixon and sold by Siegel of California as well as others.
As for the price tag:
you get four hours of instruction
you also get free advice/help directly from me if/when needed and I will also recommend additional resources to adi in your work
it is 100% guaranteed
and last but not least you get to hear me say "booger it up" more times than I ever have in the last 48 years of building leather

.............
Is it the only good resource? - nope, but those that have bought always seem to recommend it...........
FWIW - I've got about 10-12' worth of bookshelf (including the book recommended above) and a three drawer file cabinet filled with leather crafting info - IMO one can never have too much info......