With your 550D, the main issue is triggering the flash. Since the camera has no built-in wireless E-TTL controller and no PC sync port, your practical starter options are:

1. Off-camera shoe cord: simplest wired option. It keeps full hot-shoe communication, but range is short.
2. Optical slave: if your Metz can fire as an optical slave, you may be able to trigger it with the camera’s pop-up flash. This is cheap and easy, but less flexible and requires line of sight.
3. Radio triggers: the most practical wireless approach for home use. Budget manual triggers from brands like Cactus or Yongnuo are commonly recommended. These usually mean working in manual flash power, adjusting output by test shots.

You’ll also need some way to position the flash—anything from a basic stand/bracket to an improvised support.

So, to get started cheaply and with minimal cables: try the Metz’s optical slave mode first, or get a simple radio trigger set. If you specifically want off-camera TTL, that usually requires a more expensive dedicated wireless TTL system or a TTL cord.