Price comparison app

My idea is pretty simple: I want to build an app similar to PriceRunner and other price comparison websites. The difference with my idea is that I want to make price comparisons between second hand/customer-to-customer websites.For example; I want to buy a new smartphone, but I can’t afford a brand new phone, so I will buy a pre-owned phone. I start looking around at maybe Facebook Marketplace, Ebay, etc. It takes a lot of time. So what I want is an app/website which collects data from all those websites and shows me the cheapest phone for sale right now.

So my question is: Is it even possible to build an automated data collection that collects products and prices from different marketplaces like I mentioned? Would that be an incredibly advanced and tricky thing to build?I should also mention that my coding skills are pretty much zero. I only have pretty good knowledge in HTML and CSS so I would say I’m fairly tech savvy. Anyhow, I found different apps that let you build apps without coding, so I thought I would give that a shot.

I’m sorry if my explanation is not sufficient as English is not my native language. I’m also aware that apps/websites like I just explained may exist, but not in my country.

Feel free to ask questions if I need to clarify anything.