In the middle of the Greek monetary (Euro) crisis, people have discovered a way around the system that's been rigged against them. They are setting up local currency and exchange systems and doing business, effectively, without government money. The breathless story can be found at Raw Story and it is well worth reading and thinking about. But, for me, that's just the tip of the iceberg. A link in the story points to CYCLOS, open source software to set up and run an online banking system!
CYCLOS supports most of the forms (maybe all?) of community currency and barter systems. It can be accessed online, by smart-phones, and all the expected nifty ways. It has its own internal transparent credit reference system, advertisements for goods and service on offer, and a host of features that would let any group set up their own private economy outside the Sovereign Money scam. According to classical thinking, the State has the monopoly on the use of coercive force and on the creation of money. Both are based on consent of the governed. If the governed realize they can manage their own money systems, the government and it's symbiots, the banks find the economy under their control, and therefore their influence, reduced.
For the sceptical, this has been found legal in the US. Ithaca Hours is a local currency that has been running for decades. There is a rich, if little known, literature on local or private currencies.
For the Solidarity Economy, this is potentially quite important. The simple thought is that a community, committing to Solidatiry (possibly Transition), can create a money economy to support and strengthent its Solidarity activities. It could be the natural outgrowth of an established co-operative banking capability (Credit Union) or a new system. Solidarity Economy enterprises (co-ops) could use such a "bank" for trade, for exchanges amongst themselves, and for credit (if there's a business-capable Credit Union in the mix). Bottom line, for next to no cash investment, you can create a Democratic, Co-operative, Community-member-owned money!