Woot offers Used Ring Video Doorbell Pro (Works with Alexa, Existing Doorbell Wiring Required) for $74.99. Free shipping for Prime Members.

Product Description:
With a motion-activated camera, two-way audio and brilliant 1080p HD video, you’ll never miss a visitor again. See, hear and speak to whomever is at your door in real time from your smartphone, tablet or desktop. Day or night, rain or shine—you’re always home.

• Upgraded, 1080p HD wired video doorbell with Two-Way Talk and Quick Replies, Advanced Motion Detection, built-in Alexa Greetings (an exclusive Ring Protect Plan subscription feature), enhanced dual-band wifi, and customizable privacy settings
• Ultra-slim design
• Get motion-activated alerts on your phone, tablet or PC and check in at home anytime with Live View all in the Ring app
• 4 interchangeable faceplates
• 1080p wide-angle HD video
• Night vision
• Live View / video on demand
• Two-way talk
• Customizable alert zones
• Works with Alexa for voice control (Alexa device sold separately).