How to check broken in without using paid tools?

A1 Website Analyzer for Windows and Mac offers a free mode that includes up to 500 pages - you can see many things there including broken links and redirects

1) Crawl The Website
2) Click The 'Response Codes' tab & 'Client Error (4XX)' Filter To View Broken Links
3) View The Source Of The Broken Links By Clicking The 'Inlinks' Tab
4) Use The 'Bulk Export > Response Codes > Client Error (4XX) Inlinks' Export