must pay for those exceeded lor. so if your plan has little free
sms, dont anyhow use.
It depends.. if in a r/s then 1000+.. if just flirtin around
also got at least 500.... 
use msn better i think.... save $. Some ple is call more sms
less, but i dun like to call prefer face 2 face talk.. or
sms/msn