firstly hello and welcome
first question
Whistling doesnt make monsters easier as such, it means you dont have to move and the monster come to you, and also you wont go get any EP's which are harder to kill, so sort of make it easier but not what you want, you can type /set ( I believe never used it myself ) and this lowers the difficulty of mobs but also the XP, ( but note this stops working after 71, you have to grind from here.
Second question,
Trapdoors you have no say in the matter if you fall through them or not ( Except for Ninja or Rogue ) Trapdoors do make monsters harder to kill, they increase in difficulty, and as for making drops better who knoes its pot luck :D.
3rd question
makes no difference as far as im aware, some may argue different, but it makes no difference,
4th question,
rough guide to prices, sometimes certaint hings sell more,
LS item prices:
Whites:
lvl 0-15 do not sell.
20 - 1 fg sometimes sells. depends on the event, should be selling right now as bob888 is a big buyer right now.
25 - 1-2 fg
30 - 2-3 fg
35 - 4-5 fg
40 - 6-8 fg
45 - 20-25 fg
https://ladderslasher.d2jsp.org/itemHistory.php?i=1226519539&c=050 - 40-60 fg Not sold one of these recently either
55 - 90+ fg, depends on type. club/plate/chain ~90 fg, dagger axe lightning ice ~ 110 fg. Heavy weapons ~ 120-130 fg
https://ladderslasher.d2jsp.org/itemHistory.php?i=1226990427&c=0Mutables:
lvl 10: 6+ Stats
lvl 15: 5+ Stats
lvl 20: 4+ Stats
lvl 25: 4+ Stats
lvl 30: 3+ Stats
lvl 35: 1+ Stats (1x stat sometimes doesnt sell, consider shrining them if not sold within 3 days)
lvl 40: 1+ Stats
lvl 45: 1+ Stats - 2 fg each
lvl 50: 1+ Stats - 4 fg each
lvl 55: 1+ Stats - 6 fg each
for level 10-35 items, for every 2 additional magical properties add 1 fg to price, so a angelic level 35 is 2-2.5 fg
for level 40-50 items, for every additional magical property add 1 fg to price,
for level 55 items, for every additional magical property add 3 fg to price,
https://ladderslasher.d2jsp.org/itemHistory.php?i=1226984170&c=0Hope this helps

Quote (deukalion @ 11 Apr 2021 11:59)
as deukalion says id potentiall double the prices for the 50 and 55's and then slowly lower them
This post was edited by SUPER-CARP on Apr 11 2021 05:16am