Hi,
I'm new here also! I thought about starting a business to scrap for others (since everyone was always asking). But, I didn't think people would be willing to pay for materials and my time. So, I decided to start my own business to teach scrapbooking and stamping. I really like it and I think it means more to people when they do it themselves.
I'm sure in wealthy areas there is a market for your business model. I'd think about how much you'd like to make an hour (scrapping for others will definitely get to be work, so I wouldn't short-change yourself). Would you shop for the materials for the customer? sort their photos? write creative journaling? Add up the time you think it would take per page (it probably takes me more than an hour for a "from scratch" double page layout). So estimate the time plus the materials to see how much to charge. That would be my best idea of how to charge. Hope that is helpful. Best wishes!