accel
Member
I'm proud to say that I'm still F2P on my account (save buying a single pack during the beta ) and bought all the adventures and expansion cards I own with in-game gold and the dust gotten from duplicates and I'm not an infinite arena player or anything. That said, I have been playing regularly since the beta, so I just paid Blizzard with my time instead of my money. I can only imagine how tough it would be to build a sizable collection of cards if you started playing the game at a later date and wanted to stay F2P.
A data point on this: I am F2P, started an account several weeks ago (but was following the game for a long time, watched tournaments, etc). Every day or two I play a single arena run and clear dailies if they are about to overflow. The gold income from dailies is enough to keep arenas going (I get around 100 back from each arena, very roughly), so my collection of cards is growing at the rate of a pack every day or two.
Not too bad (as long as you understand that it'd take like 2-3 months of this before you can have a non-joke deck in constructed and like 6 months before you have something viable and maybe some limited options).
PS: No legendaries yet.