I jokingly said on twitter that if I invest in tracking marker I would use the DIY design Erick Alba has released and put it on
bar-coasters. At least that way it has dual use.

Now all jokes asside there are some points wich speaks for them:

- The size of the Tracking marker Erick proposes is roughly the same as a coaster.
- Their spongy surface is pretty ideal to prevent reflections
- Modifications like painting the sides, or add notes is more easily done
- The price for them is relatively low, since the printing service is more  broadly used than a custom print job.
  Also its a more refined process, so you can expect good QC during the production.
- They are lightweight but still sturdy enough
- They are a conversation starter.
- They offer more versatility attaching them to things. Think of needles

Downsides
- The might look unprofessional, I used the 6 sided ones for two reasons:
   First it less obvious what they are, second it adds 2 extra edges to track from
- you might need to paint the sides, especially if you use the colored side
- Its paper, so on the downside, you might replace them more often than
  plastic ones, you will have problems in wet environments

I think if I would ever reorder them, (wich means I would get enough profit out of them..wich I will never make)
I would invest in two separate editions, one white only and one green only version. (Instead of having them
on one coaster).
That way I could paint the sides according to the color I use, and could use the backside to put my address on them.
So if they get "lost" you can be sure someone has your address and renembers you.

I'll defintively will post an post mortem... as an amateur I have some kind of luxury to treat things
a bit, well amateurish, and see whats comming out.