Battletag : grommpy#2695 Region: ASIA Trade Only ? : Yes, you go first
While Saviors of Uldum requires too many Legendaries to have fun, in general as F2P you have enough dust to craft 1 good deck per 4 months. Spending ~$150-200 changes that to about 2 good decks per 4 months, not really worth it in my opinion. Get 3-4 A-games instead.
Most Legendaries and Epics you will not need nor craft.
Compare to Magic or Pokemon, the best decks are not always the most expensive one. Although often, they do contain specific Legendaries and Epics you are *required* to craft which is not possible if you don't complete your daily quests as F2P.