I want to create a price-comparison website/web application and join affliate programs.My problem is, when I want to join for a company's affliate program,seems like every company asks for my website.

How can I create a price-comparison website if I am not an affliate of any company?Can I create a price-comparison site without being an affliate of any company, is it legal?In this way I will not have access to their developer api, so I can get prices using web-scraping techinuqes.I actually did it with a shopping website but although my small web app (running on local host actually) waited for 20 seconds between each http requests, after about 40 http requests that website started ignoring the connection and started returning "robots" file as response body.

I didn't try it with other online shopping websites , I am actually not sure if it is legal to do that.I have read Amazon's policy about affliate program and from what I understand it says showing/getting information about an Amazon product has to be either via banner/link provided by Amazon or using Amazon's Advertising Api and that they don't allow robots.

If the only legal way of automatically grabbing price information from
another website is to use their api and to use their api I have to join their affliate program and to join their affliate program I have to have a ready website  which I would put affliate links,banners, how can I create a price-comparison site,clearly I can't add any store's price information cause I don't have access to their api, so I can't create a price-comparison site without joining their affliate program and I can't join any of the affliate programs because they require me to have a working website...

I hope someone would clear my confusion,thanks.

As to your first question, you put that to the company that asks for your website. Again, if they are not answering your question it's going no where and you are better off without them.

As to Amazon, good to read they don't allow robots.