Difference between BeautifulSoup and Scrapy crawler?

Scrapy is a Web-spider or web scraper framework, You give Scrapy a root URL to start crawling, then you can specify constraints on how many (number of) URLs you want to crawl and fetch,etc. It is a complete framework for web-scraping or crawling.

While

BeautifulSoup is a parsing library which also does a pretty good job of fetching contents from URL and allows you to parse certain parts of them without any hassle. It only fetches the contents of the URL that you give and then stops. It does not crawl unless you manually put it inside an infinite loop with certain criteria.

In simple words, with Beautiful Soup you can build something similar to Scrapy. Beautiful Soup is a library while Scrapy is a complete framework.

Source

I think both are good... im doing a project right now that use both. First i scrap all the pages using scrapy and save that on a mongodb collection using their pipelines, also downloading the images that exists on the page. After that i use BeautifulSoup4 to make a pos-processing where i must change attributes values and get some special tags.

If you don't know which pages products you want, a good tool will be scrapy since you can use their crawlers to run all amazon/ebay website looking for the products without making a explicit for loop.

Take a look at the scrapy documentation, it's very simple to use.