There are 6 combinations:
Array
(
    [0] => Array
        (
            [button] => 50
            [arrowhead] => 2
        )

    [1] => Array
        (
            [button] => 50
            [coin] => 1
        )

    [2] => Array
        (
            [button] => 100
            [arrowhead] => 1
        )

    [3] => Array
        (
            [button] => 150
        )

    [4] => Array
        (
            [arrowhead] => 1
            [coin] => 1
        )

    [5] => Array
        (
            [arrowhead] => 3
        )

)