There is an official free version of MultiECUScan but it is function/module support limited. No CAN Bus modules are supported and on some KKL based ECUs then some other functions are restricted (e.g. oil change reset on a Croma 2005).
There are no FULL function legal free downloads of MultiECUScan software. The last full function free version of FiatECUScan software was version 1.6. Up to Version 1.6 only basic KKL connection type ECUs were supported and obviously less vehicle model.
You may be able to find versions prior/up to V1.6 on the web but BE CAREFUL as they could be carryinging all sorts of rogue & danagerous code.
After V1.6 came the new Version 2 release which introduced CAN Bus support. This is purchase/licensed software only. A purchased license was for life and all upgrades.
In August 2012 MiltiECUScan V1 was released. A purchased license for these versions are valid for life but with updates for only 1 year.