Definitely get these two in the bundle package. While no questions will 100% reflect what you will see on test day, the resources from GMAC are going to be the most accurate since they develop the exam.
The exam scoring algorithm may be a little outdated based on other reviews on GMAT Club but it will likely be the most accurate when compared with other GMAT exam companies.
In terms of discounts, I would always check retailmenot.com. They don't always have discounts but sometimes it will be 10%-15% off.
If the package is not on sale now, you can always just keep an eye on discounts that may come up (assuming you do not need the materials right this second).
Even if the package is not on sale it is well worth the money. Over 400 practice questions and 2 additional exams from the test creator.