There is many free things in Second Life in freebie stores but I like the free things you can find in Linden Labs lands and things owned by LDPW (Linden Department of Public Works), there is some known LDPW stores but also many free things you just has to discover when you are walking over the lands of Second Life.
Here is a small list of things I has found by my self and with help of some friends:
* A simple barrel made by Ben Linden, free to copy at http://maps.secondlife.com/secondlife/Popke%20Tal/110/92/28
* In the North Reservoir there is many things that are free to copy or buy for 0L, but my friends favorite was the Bubble Grille made by Garden Mole, http://maps.secondlife.com/secondlife/Pengallen%20Bridge/198/240/20
* A sinuous bench made by the Garden Mole, it do contain some sit animations and a good sit script, free to copy ay http://maps.secondlife.com/secondlife/Bronlen/126/94/35
* In the protected land of Aidon can you find fish and plants that is free to copy and it is not plants from the Linden library, http://maps.secondlife.com/secondlife/Aidon/146/114/11
* A simple Second Life stone hand that is free to copy can be found in Trinoo, it is made by Silent Mole but so easy to make it may not be any point in copying it, http://maps.secondlife.com/secondlife/Trinoo/204/56/9
* In Port of Karma there is a board where you can buy several houses and objects in Zindera style, http://maps.secondlife.com/secondlife/Mosh/115/69/30
I know about more places with free things but I keep them for my self until a later time.