Help me and pricing

Hi all,

Please could anyone advise me on a price for a job please.

I have been feelancing for a couple of months and have been asked to design a 150-250page book, approx 40,000 words. It will have approx 15 images to include so will be text heavy.

I have never done a job this size before so I am finding it difficult to price as I normally quote a day rate but do not know how long this will take to work it out ths way. Also, if anyone could also give me an approximation on how long they would need time wise to produce.

Any help would be gratefully received.