Me and two of my buddies will be opening 3 boxes in about a weeks time… There’s nothing wrong with opening packs in my opinion. After all, it’s what they were made to do 
As for prices, that I am unsure of. I’ll be needing to purchase some as well to attempt to complete as much of the set as I can.
It’s the only booster box I own.
I encourage everyone out there to open as many packs as possible!
I would (and have) open some packs. It is super fun and a cool experience. Be warned that the pull rate is roughly one ex per booster box, and around 1 holo per 8ish packs.
Because of the packs only have 5 cards, one rare with one or two uncommon with two commons (some packs have an energy) and since the boxes only have 24 packs, I would say that a complete non-holo set would be $300 U.S dollars, each holo graded would be $50 to $75, each ex roughly $100, and Flygon ex being valued at the same as a pre-release Raichu because they are about as equally as rare.
Hope This helps,
P.S. @pokemonchina would probably be the best expert on this though.
I don’t know how sealed collectors do it. To me, the fun and enjoy of opening and owning the individual cards will always outweigh the financial reward of keeping it sealed, but I’m not trying to hate on any sealed collectors.
In this case (for me) i think the sealed box is much cooler than the contents so I’m perfectly happy with never opening it.
I posted about this just the other day as a reply to a similar question.
Open them, there’s about to be even more of a flood in the market. (I sold a case to a reseller)
Even though I sold LOADS of boxes, there still haven’t been any Goldstars since my graded trio. So the value is now in the Goldstars, not the sealed boxes.
I’d say these prices are about right! Goldstars a lot more obviously. Flygon EX $200+.
rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F263453140298