Why don't you look through your books and figure out what a couple of the pages cost you to make and then figure out what you'd also want for your time.
The only time I got paid for doing a book... here's my story...
My sister asked me to do a book for her... a Disney book from her pictures of our vacation in 2003. I told her no. She said she'd pay me. I said no. (I have enough of my own stuff with 3 boys.) She kept asking and then asked where she could find someone who WOULD do it for her. Fine. I'll do it, I said. I told her I'd need $40 up front for printing her pictures. She sent $50, the book (which was from Disney and had some CS in it), a box of adhesive (some already used) and some ugly stickers and borders (nothing to do with Disney.) At first I tried printing her pictures, but they were AWFUL, so I took the rest to CVS and used their machine and "fixed" each one. Cost me about $40. I finished her book, added up the cost of each page. Didn't charge for my time, adhesive or for scraps, etc. I also used my stash of like metal letters, alphabet stickers, etc and charged her $5 for this... "misc. letters". If I charged her for a sticker sheet, I gave her the rest of the unused stickers. I gave her the book and she loved it and thanked me. That was it. Never offered more money... never even ASKED if she owed me more. I stewed about it for a couple of weeks and then finally said something. I asked that instead of payment (not even $40 more), would she please buy me this kit from a monthly scrapbook club. (The club offered 2, I got one, but wanted both.) It was only $33.50. She said sure... but she didn't even know she owed me anything because I never said anything. (I gave her the book at Thanksgiving.) Well... 2 nights ago, I ordered the kit myself. After WEEKS of reminding her every time we talked, I finally gave up.
Now this was NOT a gift. I made a book for her the previous Christmas as a gift. I made two other scrapbook as gifts this past holiday. This book for my sister was something she ASKED to pay me to do and I'm STILL a little upset about it... LOL!! I won't be doing that again... either as a gift or as a paid job. Why do people think they can treat family like this? (She lives in WA, I live in SC... so it's not like we see each other all the time.)
Sorry for the vent... but like I said... I was a little more than upset about this...
Good luck to you!!