Website site scraping App

I am in need of an app that will pull out Lego sets numbers along with their price from certain websites and then compare these with what is called their part out value. The app will be written in C# and have a GUI. The GUI will have the following options to begin with • Drop down list to select the site to be scraped. • Ability to add new sites to the list • Ability to enter the part out multiplier. This could be a decimal figure (eg 2.5) • When a site is selected and the multiplier is entered the program will scrape the sites and only return results with a part out value equal to or greater than the multiplier value. • The results will be displayed on screen but also give the option to be export to csv • The source code for the project will be provided