Er... is the cron job running on the same server where your files are hosting? If so, why are you trying to execute them over HTTP? Why not just invoke PHP directly, e.g.
/usr/bin/php -q /home/domain.com/public_html/deal_of_the_day.php
EDIT: Obviously, the paths to the PHP interpreter and your .php script are just examples and should be modified to fit your host's environment.
EDIT2: Either way, are you viewing the error/output messages from the cron job? If not, why not? You should be logging this information by adding something like the following to the end of the command:
>>/home/domain.com/cronjob.log 2>>/home/domain.com/cronjob_errors.log
or, to log all output and errors in the same file:
2>&1 >>/home/domain.com/cronjob_all.log
EDIT3: Forgot to mention... output redirection syntax may vary depending upon which shell your host is using.