I want to make a website that shows the comparison between amazon and e-bay product price.
Which of these will work better and why? I am somewhat familiar with BeautifulSoup but not so much with Scrapy crawler.
The differences are many and selection of any tool/technology depends on individual needs.
Few major differences are:

BeautifulSoup is comparatively is easy to learn than Scrapy. 
The extensions, support, community is larger for Scrapy than for BeautifulSoup.
Scrapy should be considered as a Spider while BeautifulSoup is a Parser.
Difference between BeautifulSoup and Scrapy crawler?