I hate those premium collection boxes. It costs over twice as much as buying the boosters separately here (8 boosters is $48, so $6 a pack and those boxes are $100) so if you want the promos you're paying colossal overs for them.
In fact, all of these boxes and blisters and other stuff that are "better value" in the US just cost more here. The ETB are $60, the 3-pack blisters cost anywhere from $20 to $25 depending on whether it's a pin or promo blister, the promo/coin blisters are $9, tins and figure/jumbo promo boxes are $35.
It's an absolute pain. Importing from other English-speaking regions is not worth it either due to shipping costs. It's ridiculous.
of course you could buy singles if you just wanted the promos.