@Crissal has given you a good reference, and I tested scraping from your url myself. The tricky part is to get the relevant hrefs (there are many irrelevant hrefs), if you are stuck you may refer to my code.
browser = webdriver.Chrome('(your_path_here)/chromedriver')
browser.get('https://www.ebay.com/sch/i.html?_from=R40&_nkw=watches&_sacat=0&_pgn=1')
bs = BeautifulSoup(browser.page_source, 'lxml', parse_only=SoupStrainer('a'))
#this is the one liner to get your relevant hrefs, those with class='s-item__link'
ls = [l['href'] for l in bs if (l.has_attr('data-track')&l.has_attr('href')&l.has_attr('class')) if l['class'][0]=='s-item__link']
#print or save to a text file
#print(ls)
#with open('links.txt', 'w', encoding='utf-8') as outfile:
# outfile.write('\n'.join(ls))
Output from print
https://www.ebay.com/itm/SKMEI-Watch-Mens-Womens-Watches-Waterproof-Sport-Outdoor-LED-Digital-Wristwatch/392260574708?hash=item5b548d5df4:m:myDW5IBI631t2UBz65C2Ztw
https://www.ebay.com/itm/LED-Watches-Men-Women-Sport-Casual-Digital-Army-Military-Silicone-Wrist-Watch/193040878143?hash=item2cf2220a3f:m:m7VH5iopUucVEYPr9y5dfxA
https://www.ebay.com/itm/Men-Women-Leather-Strap-Line-Analog-Quartz-Ladies-Wrist-Watches-Fashion-Watch/202788343863?hash=item2f37209037:m:mOWAjJgHKIYzv8YqDPxLZqA
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