I was asked by OP to post here and this is my opinion:
TBH I am not updated anymore with the current bitcointalk account prices as I stopped accepting it as a collateral and re-selling it a month ago. But before that, I am actively involved on bitcointalk account trades making me quite familiar with the market
# Yes, price really affects the market, based on my observation. I first knew account trades way back when I attempted to sell my very first account I use here on bitcointalk (july 2015) and the BTC price that time was around $250-300. The average price for a full member that time was 0.08 BTC but I am selling mine for only 0.07 BTC. Then when the bitcoin price hit 400-450 within the last two months, you can buy it for as low as 0.03 BTC
# If an account got a trusted negative feedback, it is worthless IMO and untrusted ones doesn't matter at all to me cuz most of them were probably just a troll and also those do not reflect on an account's trust score
# Well most sellers do consider accounts with trusted positive(green) feedback more valuable that those neutral ones. Personally it doesn't matter to me cuz for me, reputation can't be bought but still, I just go with the flow
# Scam accusation only matters when the accusation was proven thus it will lead to getting a red trust score and the account will be worthless
# Regarding to ban history, its not a big deal for me if it was banned before. It doesn't really affect the price since it will not also affect the buyer when joining a sig campaign (signature campaign was the main reason why people buy accounts here). Still, I can see some buyers prefer those were not banned before.
# It depends on the loan. I don't mind if the account got a history of repaid loans, as I said , reputation can't be bought. But if the account got a history of unpaid/defaulted loans, again, it will lead to having a red trust score and then again it will be worthless
# Signed message is a must on selling/buying bitcointalk accounts as it was the most common way to prove the ownership of an account therefore accounts that can't provide a signed message from an address staked/posted long time ago (mostly they prefer an address posted/staked for atleast 3 months old). No signed message, no deal. However, some also consider those account that can't provide a signed message, it will be cheaper though. In some cases, some accounts have never posted a single addy, it will be also cheaper than usual.
# Providing a private key will be a more solid proof of ownership. It will be also convenient for the buyer cuz he/she doesn't to stake a new address for future reference. It will be a plus to the value of an account.
# Availability of good signature campaigns is also a factor to account prices. The more the available campaigns with open slots, the more demand of accounts there will be, then expect higher prices of accounts (mostly full members and sr members) cuz of limited supply. Of course there will be less demand if there are less open campaigns (or none at all)
# Just like in love, age doesn't matter
# I prefer those with cool names, still won't affect the price though
# I think what you were trying to say was those with potential activities. Of course, the higher the potential activity of the accounts, the higher its price
# Post quality is a big factor in purchasing an account cuz it was the main requirement in joining on a high paying signature campaign. You can even get special rates on a campaign if the post quality of an account was exceptional. Low post quality can just to rejection when you are going to apply on a campaign. Higher quality comes with higher price
# I don't think most popular boards/sections by posts will affect the price cuz in the end its still the quality of posts will matter, no matter what board it is EXCEPT off topic, games & rounds ,and local section
# This forum is mainly an english forum so I prefer most (if not all) posts were on english language. Those accounts with mostly local language posts will have lesser value.
Regarding to prices, here's my estimation:
1 = Brand New - 0
2 = Newbie - 0 (will only have value if it has a potential activity)
3 = Jr Member - 0.001-0.005 BTC
4 = Member - 0.006-0.04 BTC
5 = Full Member - 0.05-0.1 BTC
6 = Snr Member - 0.11-0.2 BTC
7 = Hero - 0.21-0.5 BTC
9 = Legendary - 0.6 BTC and above
10) Donator/VIP/Staff- priceless
Prices may go higher if it has potential activity
Hope this will help even though it is not that accurate
You should also contact Neotox cuz he was more experienced on such things, I used to contact him before when I got some inquiries regarding to bitcointalk account sometimes