website backend search programming

Main idea to do plane tickets website ,obteining prices from other sites but changing the price depending a factor. I want to have html code(can be any programing language) where the customer choose a flight, 2 cities(origin and destination) dates and with this information we search in few air plane companies search , extracting the flight price, multiple by factor (0.8 example) and show the price to customer. This factor its divide by 2 groups of flight companies that I will pre-determine, and also the factor, example: Group 1: factor 0.75 Companies, air france, united airlines , lan chile,etc Group 2, factor 0.80 Companies, american airlines, delta, tam,etc So if the search result is that america airlines has the best price at 1000usd (backend)it will show the exact trip(date planes,connection,time of flight etc) but at 800usd(1000*.8)(frontend). Then the normal confirm purchase,create order , credit card process etc.(database) I don't want the design of website,I will do it, I want the programming for the explained above when the customer fill the information and click search.