I have just finished working on this bookshelf unit. I built it from 100% reclaimed wood-not free though, I paid ( client did to be precise) fair amount for it, but I must say-it was worth it. Before I visited this used timber place ( http://www.emagine.info/2014/11/13/trip-unknown/) I went to few lumber depots to see what they got and compare prices. It is true though-it was cheaper to buy fresh pine boards, than to get it “refreshed”, but the looks of the furniture speak for itself.
The only finish I have applied was teak oil, it did darken the wood just a bit, but brought out all grain and cool looks I think.
A bottle of teak oil was absorbed by these shelves and 3/4 of clear satin varnish.
Cool feature is the option of stacking them up whichever way you like, that makes this project more interesting. And this picture comes from my client`s house, as you can see-he chose to go lower and wider. I will try to get more pics soon.