Some Arduino components seem ridiculously cheap
The cheaper option is not always lower in quality. You can find items for sale on Amazon, Ebay and Aliexpress that all have the same "seller name" and a identical picture of the item. The price is usually 5 to 10 times higher on Amazon than Ebay. Aliexpress is usually the cheapest.

During the past year, I've ordered over 100 Arduino related sensors/modules from Ebay and Aliexpress. Four from Ebay and one from Aliexpress were defective. I got a refund for all five items.

If you are going to buy the cheaper products, it's a good idea to order more than you need in case one is defective.

Some items should not be sold at any price. For example, I purchased a DHT11 temperature and humidity sensor when I first started with Arduinos. It's an inaccurate piece of garbage, and that's exactly where it went.