eBay has the Remo+ DoorCam WiFi Smart Over-the-Door Camera, (DCMU-1706) for $99 with free shipping.List price: $199. It fits over your door and features a 160° field of vision.

$99 Shop Now

Amazon has the Annke Nova S 1080p WiFi Security Camera with Two-Way Audio (AU-I41HG0102) for $21 with free shipping on $25+ or with Prime. Works with Amazon Alexa and IFTTT. Has good Amazon Reviews.

$21 Shop Now

Amazon has the Ezviz 8-Ch 4-Camera 1080p 2TB IP NVR Security System (BN-1824A2) for $370 - $40 off with coupon (Clip Coupon) = $330 with free shipping. Retail price: $800. Has good Amazon Reviews.

$330 Shop Now

Amazon has the Ezviz 1080p WiFi Outdoor Security Camera for $89.99 - $13.50 off with coupon TXHGVSF6 (Ends 2/28) = $76.49 with free shipping. It features a 1080p video recording, 360° swivel base, night vision up to 98 feet & motion detection with alert siren/strobe light, 2-way audio, microSD card slot, alerts and remote access via mobile app.

Has good Amazon Reviews.

$76 Shop Now