- 5-Port Gigabit Switch for $20 (expired)
TP-Link (TL-SG105E) 5-Port Gigabit Switch for $20 for the next few hours.
They call this a "Smart Switch," which gives some basic management features.
Unlike a regular (unmanaged) switch, the this lets you monitor the switch's traffic, enable QoS, and do port diagnosis.
These basic management features are things most users will never use, but the idea that you can monitor and diagnosis connection problems could come useful when you are experiencing problems.
It normally sells for about $33 and has a lot of positive reviews, so $20 is a great deal.