Scrapy is a good way of scraping the data, but then you still need to figure out how to store the old value, and repeatedly run the scraper to check against it, and send a notification.
For simpler sites, without much page navigation, only using requests and BeautifulSoup is usually easier, I'd only add Scrapy into that mix to handle crawling through multi-page navigation.

Zyte (made by creators of Scrapy, formerly ScrapingHub) have a PaaS offering for doing automatic hourly scrapes, and within that you can call external services for notifications.
I'm working on price drop notification application and I'm thinking of using Scrapy for that but, I am not sure how to use it for that, do i need to check the product price regularly after specific interval or is there any other way of doing that.
How to use Scrapy for price update