
First, as with any giveaway or sweepstakes, read the rules. Make sure you are eligible. Sometimes these are open worldwide, sometimes only to a certain country (usually the USA, Canada, or Australia.) I even have seen one where the marketing agency the blogger is working with was
willing to accept winners from Canada, but the service they were giving the code away for was not able to be used in Canada. That would be disappointing if you spent time entering that only to find out you couldn't use it. Otherwise bookmark their blog.