UntilGone offers the refurbished 2nd-generation Tile Bluetooth Tracker for $9.99 plus $1 for shipping. That's around $18 less than you'd pay for a new one elsewhere. It attaches to something that you don't want to lose, such as keys or a backpack, and can be tracked by Tile's mobile apps, as well as Alexa. (The battery is non-replaceable.)

Need more? You can also buy the following multi-packs, with lows against what you'd pay new:
  • 2-pack for $17.99 + $1 s&h (low by $39)
  • 4-pack for $29.99 + $0 s&h (low by $13)
  • 6-pack for $42.99 + $0 s&h (low by $29)
Note: It's covered by a 30-day UntilGone warranty.