If he sells all 50 that he has, he'd net an average of $1020 per logo. (First one was $40, price increases by $40 per logo, last logo is $2,000, total net is $51,000)
That's a highly unlikely "if". I doubt they'll sell any logos for much more than $400, which averages "only" $146.66 per logo. That's pretty good one-off revenue if the logos were already finished, especially considering they can probably sell the remainders on the side for some extra cash, but it's probably not a sustainable business model.
