Build an Online Store

i need a script that can automatic update the products from store - magento/wordpress from source providers. Source providers at least 5 - that have different products exposed (ex: p1 - has b2b - you can access b2b with user and pass, p2- has different b2b - accessed by user and pass, p3 - has daily excel reports with stoc - products on stoc, , p3- has weekly excel with stoc. We need a script that can search all providers databases, look up after a product and choose the cheapest one from that databases and put in our store. (all distributors, including thouse with b2b access can generate an excel with stoc products)