(1) when x≤15, y = 411 (x-8)-811 = 411x-4111;

when x > 15,

daily sales: 411-41(x-15)=1111-41x, and the profit of each copy is (x-8) yuan,

y = (1111-41x) (x-8)-811 =-.

(2) The meaning of the question is: 411x-4111≥1211,

The solution is: X ≥ 13.

Therefore, the price of each set meal should be set at 13 yuan.

(3) When x≤15, the maximum value of Y =2111

When X > Make the daily sales volume larger, but also have a higher daily net income.

∴ When x=16, the maximum y =2181.

To sum up, the price of each set meal should be set at 16 yuan, and the daily net income at this time is 2181 yuan.