Yes, I have a metered broadband connection at home and foolishly launched the daemon with over 150 days to catch up yesterday - promptly hitting my broadband cap two weeks early - oops. It must have used several GB (unsure exactly how much as my supplier is useless with available stats). I need to look into general utilities to limit total daily data usage.
If you are operating under capped or metered bandwidth the optimized method to do a sync is here: https://bitcointalksearch.org/topic/m.12285629
This is probably somewhat more bandwidth-efficient than even downloading an old Boost-style bootstrap.
When 0.9 is released, the bootstrap will switch to an export format that is more bandwidth efficient and will be a good alternative to the above, somewhat complex, procedure.
The bandwidth limits are mostly useful for controlling other users' ability to sync from your node, or for limiting current bandwidth usage below your physical speed for connection sharing purposes. If you slow down your own syncing, it will just take longer, and the same overall bandwidth will be used anyway. If you limit bandwidth below the rate of actual usage you will just drop off the network, though current usage level is low enough that isn't likely to be an issue yet.
