I can pay 0.1btc for the account.
U must be jocking...
This is why you should state the price you're after and see what offers you get otherwise you will get lowballs from jokers. Senior accounts aren't worth that much anymore though so I wouldn't expect to get much more than double what he offered.
If you can provide a signed message from a post with at least 3 months old, also if the negative trust is from a people who have a red trust rating with 'Warning: Trade with extreme caution!' tag, then the account could worth 0.2 BTC. This is the market price, so you may make this as the ask price.