Claudia Krysztofiak wrote:
Take your hourly rate and find out how much hours you will have to work on the project per day, multiply these figures with each other and you have your daily rate.
If you do not have an hourly rate, check how much work you normally can do in one hour and how much money you would get for it (e.g. 300 words for 0.10 EUR per word would make 30 EUR per hour).
This is what your time is worth and this is what you should charge, then. Of course, plus VAT if applicable.
I fully agree with what Claudia said. And as suggested by Sylvano, you must analyse the offer critically.