(1) According to the meaning of the question, the first, second and third prizes can be set as compasses, notebooks and ballpoint pens.

At this time, the cost is 4×4+6×3+20×2=74 yuan.

(2) If the unit price of the third prize is X yuan, the unit price of the second prize should be 2x yuan.

The unit price of the first prize is 4x yuan, which means 4X+6X+20X ≤ 200.

The solution is x≤4 16 (element).

So X can be selected from 4 yuan, 3 yuan and 2 yuan.

So 4x should be 16 yuan, 12 yuan, 8 yuan,

Then 2x should be: 8 yuan, 6 yuan, 4 yuan.

Looking at the unit prices of various prizes provided in the table, we can see that 16 yuan, 8 yuan, 4 yuan, 8 yuan, 4 yuan and 2 yuan are suitable for the title.

Therefore, there are two purchase schemes: Scheme 1: The unit price of prizes is 16 yuan, 8 yuan and 4 yuan in turn, and the required expenses are 192 yuan;

Scheme 2: The unit price of prizes is 8 yuan, 4 yuan and 2 yuan, and the required expenses are 96 yuan.

Thus, the most expensive scheme needs 192 yuan.

A: The most expensive plan is 192 yuan.