Yoyo.com currently has a few coupon codes good for LEGO. Right now, you can get an additional 20% off when you use code TOYBONUS (code expires March 31st, 2014). This includes Jabba’s Sail Barge which is currently listed for $95.99 (reg.$119.99). With the code, you can get it for $76.79 (reg.$119.99) which works out to be 36% off.
You can also get 15% off 2+ Lego Creator sets with coupon code CREATOR15, 15% off 2+ LEGO City sets with CITY15 and 25% off LEGO Duplo with BIGBABYSALE. Even better, some sets have been reduced already making savings even better. (note that these coupon codes have different expiration dates)
Finally, they are offering a $40 Gift credit when you purchase the LEGO Mindstorms EV3 set (expires May 31, 2014).
Thanks to forum member LilBlossom and MagnusReign for the heads up.