I seem to have been wrong, they are Linden dollars and can be cashed out through paypal , Here's another link.

https://community.secondlife.com/t5/Linden-Dollars-L/qa-p/sla_linden_dollars

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again