No one buys Jr. Member as far as i have seen
Full member may go for around 0.07 to 0.1;
Hero member may go from 0.1 to 2 BTC
Legendary member may go for really higher prices (although I've never seen one on the selling category)
Doubt hero accounts will go for less than 0.4, 0.5. Maybe that if seller is in a hurry or account has problems. More likely to go higher. Especially if it's close to legendary. What will go for less than that is senior accounts. Maybe between 0.1 and 0.5.
I don't understand why anyone would want to buy an old account unless the use is for sig campaign spam or some other nefarious scam.
It's a very quick return for signature campaigns. It beats waiting endless months to rank up. If the campaigns didn't exist there'd be very few sales and we'd have to assume it was scammers.
I wonder if any paid shillers/ fudsters have bought old accounts to give themselves more credibility.
Think that happened with a hero account and a ponzi scheme. Not sure though.