How can I show price comparison in my own website for different products from different ecommerce websites

I want to show price comparison in my website for different products from different ecommerce websites. For example If a user types "Speakers" in my website, it should display speakers/speakers related products like

1. Speakers(2.1) from Amazon 2000 INR

2. Speakers(2.1) from Flipkart 2400 INR etc

One thing what I can do is being an affiliate to Amazon, Flipkart kind of networks and use the API's they provide. And I have an other option to use web crawler which I would not prefer. I want to know is there any other way I can do it?

Thank you in advance.