I have never seriously considered a .im domain name so consider this an amateur appraisal. Since 2006 anyone can own them, so although the population of Isle of Mann is undoubtedly what
@gilescoley says, I don't agree that is the only potential market.
So have they ever sold? According to Namebio there have been 67 sales with a median price of $1180. That is a little deceptive, since they allow one, two and three letter names, so some of these were for really short versions.
Among the single word sales were mom ($105), age (100), email ($999), auctions ($250), bus ($2735), rail ($1328), power ($999), wine ($1180) etc. (can search them all on Namebio). Surprisingly some double words sold for decent amounts. No sales yet in 2018, although 9 in 2017 including one at $3500.
Almost all the sales on Sedo, so that seems the venue for this extension, although the second highest sale ($7000 for mobile) was on the Afternic network.
Since im is shorthand for real estate in a number of European languages, I would probably try to promote it as a place for real estate quotes, as opposed to quotations in the conventional sense.
If it was me I would ask very low $$$ but be willing to take anything mid $$. It is probably a bit of a challenge to sell.