The official eBay policy:
http://pages.ebay.ca/help/sell/bidders_overview.html
It can only work properly if all sellers take the time to file every instance on non-payment. Too many sellers seem reluctant to leave strikes for their non-paying buyers.
The seller files an Unpaid Item Dispute.
If the buyer still does not pay, the seller can close the Dispute and get her fees back.
The buyer gets a Strike.
Neither can leave feedback (often a blessing for the seller).
EBay will not say how many Strikes a buyer can accumulate before being removed from the site.
The buyer can have one Strike removed, because everyone makes mistakes.
Sellers can set up their Seller Preferences to Block buyers with two or more Strikes.
You can also add a Block against bidders who do not have active Paypal accounts, which is often a reason for slow or no payment. Basically utter confusion on the part of the buyer. 
If you check the link I provided above, on eBay.ca it states:
eBay's policy for non-paying bidders is:
- First offense: warning
- Second offense: warning
- Third offense: indefinite suspension
Now, we all know that is not factual. I suspect the folks at eBay.ca simply forgot to update that page (it seems very old).
On the other hand, on eBay.com, the policy states:
"Excessive unpaid items on a buyer's account may result in a range of consequences, including limits on or loss of buying privileges. Even if you don't have excessive unpaid items, we may limit your buying until you've established a good buying history or paid for the items you've committed to."
Hello 'brenda',
If you are really in a tither about unpaid items, you might like to consider setting up your listings
with Immediate Payment Required.
http://pages.ebay.ca/help/pay/require-immediate-payment.html
Auctions are good for those rare one-of-a-kind items which are sure to appeal to many people.
Buyers interested in your items may not be willing to wait a week to get it, not if they are by nature
impatient and have found the same or similar elsewhere. Young people tend to want their items now,
so listing at a competetive 'buy now' price may be a more agreeable option.
When you offer 2 prices, - 1 buck if they bid, or 5 bucks if they 'buy', - which do you think they will choose?
Unpaid items are part of life on ebay if you run auctions. Do your bit to discourage this by filing
an Unpaid case against all non-payers (after you have send a friendly reminder, of course).
Certainly you will want to add any offender to your Blocked bidder list. But if you set your seller
preferences too tight you will greatly reduce sales. Block people with unpaid items because a
non-payer is of no value to anyone, not in business at least. Blocking users without paypal accounts
will not stop unpaid items (any kid with a bank account, even an empty one, can get a paypal account)
however it will cut you off from all that credit card revenue -- which is why so few sellers do it.
The only obstacle you may have with Immediate Payment Required is that people who wish to buy
multiples (using the ebay Canada site) and do not yet have the Shopping Cart feature, these buyers
will find it particular irritating to be expected to pay one-by-one.
If you are listing in US dollars and most of your sales go south of the border, that won't be a problem.
You say you are new at this so you will have to play around with the choices a bit to find what works
best for you, - factoring in your own inherent disposition plus that of your buyers.
Happy selling! 
