This is a common asked question about credits an I am showing an example of Developer Income page.
Where are my promo credits my balance says 0
My sale Page for today: {As an example}

The answer is You received a developer token because the buyer bought with promo credits.
you received ::::1 dev token
Promo Credits are free credits received from IMVU. You earn them when you sign up for a new account, a friend signs up and
spends money on imvu or the free spin and other promotional offers from IMVU.
Because these credits are free the developer receives nothing but a token. Worth almost nothing. 10 credits {whoopee}
The Dev tokens can only be used when submiting a product.
I lost 1250 credits on this sale.
My opinion on this is if you sell something over 1000 credits in profit the developer token should be worth the submission
cost for IMVU ONLY fees. You would still have to pay the mesher for the derive cost. And developer token should be worth 100
credits minimum. But it is my opinion.