Currently, there are 3 or 4 vendors in the USA which sell Bosios. Price various by up to 20-25% if you buy in bulk.

There is only "one" vendor selling Monarks in the USA. That person is pretty pricey, with high markup.

There are a few vendors on Ebay selling "Bosch", but the pricing on some of them leads me to believe they are Chinese knockoffs. The only way to tell is buy the nozzles and hold the plastic tube next to a flame and the real Bosch logo will show up in a light blue color. But, you're stuck with either the real McCoy or junk.

You can buy Chinese made nozzles for less than a $1.00 USD a piece, but not sure how they will hold up. Actually, shipping is more than the nozzles from mainland China. I investigated this route a year ago or longer and there was zero interest on any forum. I was ready to squeeze the trigger on buying 1,000 nozzles and no dice.