How can you spot fake websites?

Back when I first got into pc gaming, I had a gaming laptop and a regular mouse. I went on the internet to search for cheap gaming mice and found a website where they were selling a gaming mouse for $5. I’m thinking, “Wow, that’s a good deal as regular gaming mice were $30+. I didn’t immediately ask for my mom’s credit card as I wasn’t that juvenile. I got on the internet and verified if the site was legit or not and checked to see how other people rated it. After I did my research, I found out that there was no one talking about it and I couldn’t even find a single review on the website itself. Even though I was in middle school, I was smart enough to discern a real website from a fake/scam one.”