Amazon currently has the following sets on a notable discount which I think are good buys. Please keep in mind that prices can change anytime.
LEGO Chima 70009 Worriz Combat Lair $33.59 (52%)
LEGO Castle Forest Ambush $7.49 (38%)
LEGO LOTR 79006 The Council of Elrond $22.09 (26%)
LEGO Star Wars Jabbas Sail Barge $88.41 (26%)
LEGO Star Wars AT-TE $66.31 (26%)
LEGO Friends 41026 Sunshine Harvest $14.99 (25%)
LEGO Friends Dolphin Cruiser $52.49 (25%)
LEGO Ninjago 70724 NinjaCopter Toy $44.99 (25%)
LEGO Disney Princess 41050 Ariel’s Amazing Treasures $10.39 (20%)
LEGO Disney Princess Rapunzel’s Creativity Tower 41054 $31.99 (20%)
LEGO Disney Princess 41053 Cinderella’s Dream Carriage $23.99 (20%)
LEGO Disney Princess Ariel’s Magical Kiss 41052 $23.99 (20%)
LEGO Disney Princess 41051 Merida’s Highland Games $15.99 (20%)
LEGO Friends Downtown Bakery $23.99 (20%)
LEGO Friends 41037 Stephanie’s Beach House $39.99 (20%)
LEGO Friends 41035 Heartlake Juice Bar $23.99 (20%)