What should I charge for writing scripts for short 5min. animations for Kids?

Question:

What should I charge for writing scripts for short 5min. animations for Kids?

I have been writing short plays and sketches for a few years now.
Having submitted some ideas to a new animation studio, I have now been asked to write the shows themselves.

Obviously, I have to pay the rent.

I am new to the business, and am not sure of the standard fees (if they exist).

I am not a US resident and am currently working abroad (mostly with music projects)...as such I do not belong to the writers guild or any other such union.

Please let me know.
What amount in Dollars(US)?
Should I charge per episode? -per season?
Should I accept a fee and ask for a percentage?
And what of Royalties?

What should I charge a for writing scripts for short 5min. animations for Kids?

Best Answer - Chosen by Asker:

500 and up per episode.