For reference here is the markups toysrus.com is advertising based on the MSRP prices straight from lego (rounded up to nearest percent):
79100 Kraang Lab Escape - 90 pieces, $12.99
TRU price: 17.99 (39% higher)
79101 Shredder's Dragon Bike - 198 pieces, $24.99
TRU price 34.99 (40% higher)
79102 Stealth Shell Persuit - 162 pieces, $19.99
TRU price: $27.99 (40% higher)
79103 Turtle Lair Attack - 488 pieces, $49.99
TRU does not seem to carry this
79104 The Shellraiser Street Chase - 620 pieces, $59.99
TRU price: 79.99 (34% higher)
79105 Baxter Robot Rampage (Hard to Find) - 397 pieces, $39.99
TRU price 34.99 (12% higher)
If you can get a good discount via coupons or promotions, more power to you, for everyone else, for every set other than the Baxter set it is probably worth waiting it out unless you are impatient
