at anything from two hundred pounds 最低200ポンド以上いくらでも払って
who would be aghast = though they would be aghast
aghast = struck with sudden surprise
It is probable that we have (all at some time or other) had the experience ....
So-and-so must have written that = It must have bee written by So-and-so
(In such a case), it is often / [not the thought (that strikes us / (as familiar) (so much))] / (as the way (in which the thought is expressed)).
not ~ so much as = not so much ~ as ~ よりはむしろ
It is not ~ + it is so much as か？