You can reuse the netpots. Just clean them between plantings. Eventually they will break, but you can probably get 3 to 5 "seasons" out of each one.
I suspect you could make some pots cheaper out of plastic cups or something, but your labor cost would probably, in reality, make them more expensive.
I can't speak to rockwool as I don't use it.

What media do you use griz? I am not dead set on rockwool, it is just what we were recommended.

I am currently using hydroton. I've grown successfully with lava rock, river gravel, marbles, and coir.
I like the lava rock but it is too large for 2" pots. You have to break them up to really work in those small pots and that was too labor intensive. In an EnF system though, they work really well.

You can reuse the net pots for 3-6 seasons, just clean with bleach. You can reuse hydroton. What I do is wait till I get about a gallon full, then stick them in an oven 350 for 30 minutes, on a cookie sheet. Take an air pump and blow all the small stuff off. Been using more and more hydroton this season. Easy to work with. Using it in 3" net pots and in 3 gallon pots/tubs for the bigger plants.

Thanks, I am going to experiment with about a dozen in chior to see if that works well as a media, much cheaper than rockwool just not sure how it will work in a nft. I would rather buy pots that last 3 seasons than rockwool that lasts one planting.