Help with price comparison website (insurance, banking, etc)

I'm looking for some help creating a price comparison website for insurance and banking. I'm experienced in creating various types of website with PHP and MySQL but I've never created a price comparison website before and I don't know where to start. I'm looking for someone to give me some guidance on what is involved and let me know what kind of price I'm looking at. I'm assuming the website would need to link to each insurer/bank's website in order to obtain quotes but I don't know how this would work because insurers don't seem to have APIs. Any advice would be appreciated. Thanks for your time.