Questions about Amazon affiliate, Clickbank and then some

Hi, I am new to the IM world and I have some questions;

1. Do I need to have a working website to be an Amazon affiliate? I am fairly new in internet marketing and I don't have a website up and running yet.

2. Amazon vs Clickbank. Which is a better platform to start with as an affiliate?

3. Which is easier to promote? Physical goods or Digital goods?

4. Do you find the product you want to promote first then do the keyword research OR research first then find products?

5. I am really having trouble when doing keyword research. Most of the niches that I chose and did keyword research on have really high competition (according to Market Samurai) and I have run out of ideas for more niches. Any tips on making keyword research easier and more productive? I've spent the last few days working my brains off only to end up with a terrible headache and feeling disappointed because I was back where I started.

I have been following some free online programs on internet marketing, mainly the 30 Day Challange and the lessons from Affilorama. I don't have much cash to spend other than domain and hosting. I would like to invest on some materials in the future but for now it is just not possible. Although there are some tempting offers on the WSO section that are reasonably priced (less than $20) and looks to be worth it. But for now I just need a hand guiding me in the right direction. Thanks in advance.