The $500 vs $3,200 quotes usually mean you're not being offered the same thing. $350–600 is a realistic range I've seen from brokers for straightforward placements, but I wouldn't call it the official baseline. Outlook India's own published terms are a better reference point, and they currently specify nofollow links for these posts.
I'd ask the seller for the exact section/subfolder and a live example from there before comparing prices. Check the link attributes, whether the page is actually indexed, how long the placement is guaranteed to stay live, and what's included in the $3,200 quote. If it's just the same placement with some agency handling added, then obviously you're paying a lot more for the middleman.