Ellis Island has a wonderful steak special (I think $6.49) and a $3.99 steak and eggs special served till 11 a.m. in the coffee shop. They also accept American Casino Guide and Las Vegas Advisor 2 for one coupons. if you go for the dinner try to get there by 4:30 or there probably will be a big line. They also brew their own beer and root beer.
The California (downtown) has a number of breakfast specials good until 9 a.m. South Point also has some very cheap breakfasts but I think they end pretty early. You also can get a Freemont Street Experience coupon sheet that will give you 2 for 1 buffets at Main St. Station and Fremont. Buying an American Casino Guide of Las Vegas Advisor membership will both pay for themselves with the coupons they contain.