(1) needs at least 2*20+3*6+4*4=74 yuan.
(2) There are three purchase schemes, the third prize, the second prize and the first prize are respectively (ballpoint pen, notebook and compass); (compass, pen, photo album) (pen, photo album, pencil case). The most expensive is 5 * 20+8 * 6+10 * 4 =188 yuan.