Well, I'd say about $50 would cover it. It'd come with the rear shelf carpet attached.
Seriously, though, what I can find is that's actually a decent price for it. New, they're $182, or if you can find one on ebay, it's about 20 Euros plus shipping from Ireland.
https://store.paramountauto.com/oem-parts/porsche-cargo-net-98755163300
https://www.ebay.ie/itm/PORSCHE-BOXSTER-986-STORAGE-NET-CARGO-NET-986-551-633-00-JJ16-/272849769068
-Jason