Check the DAZ Fast Grab at least once a day.  The Gen 4 and Gen 5 bundles have been in Fast Grab more than once in the past year.

Also keep an eye on major promos.  During either the PA sale or the PC anniversary last year, if you spent so much, you could pick one of several bundles for free. 

Keep you eye out for DAZ Originals sales.  Between sale discounts and PC membership discounts (if you are a member) there have been times when DAZ Originals have been on sale for as much as 71% off original price.

If you are interested in the PC (if you are interested in V4 and M4, that's where you'll find the best deals on just about anything you'll need) the best time to join is usually during the PC anniversary sale in October.  DAZ usually ups the standard 30% discount to 40%.  They used to offer some really decent one day deals but that's kind of gone by the wayside.

M4 and V4 are useful figures to have as there is a huge catalog of products both free and for pay available for them and they will work in every version of Poser from P5 on up and in DAZ Studio from version 2 on up.