<?

$str = '0,0,0,3000,7000,2000,1000,1000,0,0';

var_dump(explode(',',$str));

array(10) {
  [0]=>
  string(1) "0"
  [1]=>
  string(1) "0"
  [2]=>
  string(1) "0"
  [3]=>
  string(4) "3000"
  [4]=>
  string(4) "7000"
  [5]=>
  string(4) "2000"
  [6]=>
  string(4) "1000"
  [7]=>
  string(4) "1000"
  [8]=>
  string(1) "0"
  [9]=>
  string(1) "0"
}