I don't think there's a market rate for that. But it costs 1.5x the amount of ecs as a cat and gives 1.5x the amount of drops and cash. So 1.5x whatever cats are worth.
I joined open ds for 3c. I think u can do 3 to 4c (or 5? lol) as ds parties requires more ec to start.
I always do 3c for Dog Star, I do it with 2 DNs but I've noticed some mercs who join they don't have DNs. Just shows some will pay 3c with no DNs 😏
I usually use the word “open *ec party*” since most of the club that do ec parties have close door policy😅 however noted. Wont use that again lol