I've never used the powder, only the liquid. The only stuff I've used is imported from Spain, and by the way, it's called "tinta de calamar" in Spansh.
The best value is the 17-1/2 oz (1/2 kilo) jar from Markys for $46.
Squid Ink Buy Online at Marky's Gourmet Food Store
If you can get by with less, you can get 2-1/4 oz from La Tienda for just under $20.
LaTienda.com - 2-Pack - Tinta de Calamar (Squid Ink) This is enough for about 3 reasonable sized
arrozes.
If Markys can't get it to you fast enough cheap enough, a lot of caviar suppliers have it in stock. I have no idea who's local to you, but you do.
Buena Suerte,
BDL