Build an Online Store

Greetings I want to build online store that will list products of other eCommerce websites and enable customers to order those products from my store . The websites from which I want to copy product feeds do not have API / XML products feeds so we have to set a mechanism that will allow to 1- Automate crawl / scrap / copy eCommerce product feeds from other websites in a large number for entire category / subcategory ( not copy product by product ) 2- The Crawled / Scrapped / Copied data will be including product description , image , price , variations like size and colors 3- After the product feeds are crawled , I want to set my own price for example ( 110% of the copied product price ) so the source site price will not appear 4- keep the gathered product feeds be auto synchronized or updated periodically to remain valid and to reflect any change in price or any other input . 5- I want to make checkout in my webpage and using my own cart and payment gateways , after the order come to me I will fulfill the order from the source website through drop shipping I have an example : [login to view URL] / [login to view URL] those are listing from Amazon but in my case will crawl from 5 or 6 small stores not included any big marketplace Please provide quote for that and advise how you will do it and your similar experience