I guess the armybook is priced inline with the uniforms and heraldry books which have come out recently... similar in size, quality and price.
Regarding the monster: It does look awesome. Rumors also have the current giant getting a points reduction with upgrades like the chaos/beastie one... but yeah, its a Spider-don, really (with upgrades just like one. Caster mount with stubborn idol/regular beastie/net or rock lobba options too.)
Personally, I like that Savage Orcs will have the options for bows... and that the Savage Orc Boar Boys will be able to take two choppas while being mounted (and get +1atk while doing so.) With the rumored +1str in the first round of any combat with any weapon this will be a huge bonus for the greenskins.