That depends on what the cron is scheduled to do. Normally, crons are only used for internal changes, such as updating stats counters, or creating backups. If you have the specific commands, it would be easier to analyze.
It should not affect to your web site bandwidth. If you use like wget http://somdomain.com then it should consume your bandwidth. Kailash
Im using cron job with my new blogs, and all I can say is cron job is powerful Thanks for the fast reply guys.
Nope it does not, cron job is server related thing. However if you have cron job to back and transfer database to some other server, thats surely going to take b/w.