The comments more confuse me than clarify the meaning. I see my problem already in the meaning hints for αρκετά, "very", "fairly", :rather". "very" means it's really expensive, whereas "fairly" and "rather" take that down a bit. If I were to put them in line it would be: "fairly expensive", "rather expensive", "expensive", "very expensive". What is the real meaning in Greek anyway?
It think the best translation from the Greek phrase would be 'the wood is quite/fairly expensive', not 'very' or 'really' as you suggest, which have very distinct meanings and exact matches to Greek. 'Quite' of course may mean 'very' in such a context or 'faily' which is the closest to what the phrase means. I think that your suggestion is too strong for what is implied here.