That assumes that the desktop is sufficiently old to still have an ide cable and the OP mentioned a laptop .If you just want to retrieve a few files from that, and you have access to a desktop machine, you may not need to buy anything.
You can mount a HDD like that as a secondary drive in a desktop machine by plugging it into the ribbon-like IDE cable which is already inside the computer. It means opening up the computer to attach it, but when you boot up, it should just work automatically. As well as the IDE cable, there will also be a power cable to plug into it.