Reddit reviews The Amazing Spider-Man Omnibus Vol. 1

Amazing Fantasy #15 followed by Amazing Spider-Man #1.

This is a wonderful high-quality printing

The Amazing Spider-Man Omnibus vol.1, there's 3 volumes so far!

I did a quick search for you and you have a couple of options actually (which is really surprising):

• Omnibus
  
  
• Trade
  
  
• Digital
  
  Hope that helps :)

You can get them in omnibus or big book version.

Here

The link below is the easiest way to read them.
But if you want single issue comics be prepared to shell out cash. Amazing Fantasy 15 goes for roughly 60,000 in good condition.
If that's your goal I recommend you go on eBay look for collections you can purchase or your local comic book store mine caries tons of older back issues. Also you may get lucky on Kijijji and find some collections available for purchase.

https://www.amazon.ca/Amazing-Spider-Man-Omnibus-Vol/dp/130290082X/ref=pd_bxgy_14_img_2?ie=UTF8&psc=1&refRID=XE8MGR3A8CJ447KXX29C

Also this, [Amazing Spider-man Omnibus Vol 1 which are the first 43 spider-man titles ever made.] (https://www.amazon.com/Amazing-Spider-Man-Omnibus-Vol/dp/130290082X?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-ffab-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=130290082X)