How Many Emails Could A Bidder Receive?
For emails you can see all the outgoing emails under Communication -> Email Manager.
Anyone registering, or purchasing an item, would receive an email acknowledgement/receipt.
Out Bid Notification Email
When bidders are Out Bid they will receive a Notification (see Notifications for more details).
Winning Bid Email
When the online items close there will be an item won notification sent to the winner, but nothing else. If someone bids on an item and they do not win, they would only get the Out Bid Notification at the point they were out bid.
The Out Bid Notification and Winning Bid emails are sent by default. They can be toggled "OFF" in the Online Bidding Notifications panel.