agent alert system in c#/.net

We have an existing travel website/database that needs to have added 2 agent alert features. The systems that needs to be developed are the following : 1. Destinations and before/after date match agent. The user will choose the destinations and the "after this date" and "before this date" limits that he is interested in and his email. Then this data will be added to a "agentAlertUsers" table. Then if a holiday is found in the holiday table that matches the users criterias an email should be sent out to the user with a notification that the holidays that matches can now be found on the website - and it should also show a preview of the matched holidays. 2. "price discount match agent" The user should be able to "add an agent to each of the holidays that he wants to be notified of if the price is lowered. If the holiday lowers its price then an email should be sent out to the user. Both systems needs some sort of notification system that checks a number of times per day if matches are found between the holidays in the database and the users in the "agentAlert" tables