Other World Computing offers its OWC Data Doubler Hard Drive Bracket for Mac mini, with deals starting at $25. Shipping starts at $1.79, or get free shipping on orders of $49 or more. Depending on the kit you choose, that's as much as $16 off and the lowest total price we could find. This bracket allows you to add a second SSD or hard drive to your Mac mini. Kits come with or without a toolkit, and up to a 3TB hard drive or 480GB SSD. A couple of best bets: