PHP, 89 84 bytes

foreach(count_chars($argv[2])as$a)$b+=[2=>1,3,7.77][$a];echo$argv[1]/100+($b?:.1)|0;

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Input from command line, output to STDOUT:

$ php lucky.php 99 3333
8

$ php lucky.php 0 2522
3

$ php lucky.php 0 abaa
3

Or using the same method as the ASM answer above:

PHP, 103 bytes

for([,$c,$s]=$argv;$i<4;$l+=$r)if(2<$r=substr_count($s,$s[$i],++$i)){$l++;$c+=77;}echo$l+=$c+10*!$l>99;

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PHP, 89 84 bytes

foreach(count_chars($argv[2])as$a)$b+=[2=>1,3,7.77][$a];echo$argv[1]/100+($b?:.1)|0;

Try it online!

Input from command line, output to STDOUT:

$ php lucky.php 99 3333
8

$ php lucky.php 0 2522
3

$ php lucky.php 0 abaa
3

PHP, 89 bytes

foreach(count_chars($argv[2])as$a)$b+=[2=>100,300,777][$a];echo(($b?:10)+$argv[1])/100|0;

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Input from command line, output to STDOUT:

$ php lucky.php 99 3333
8
$ php lucky.php 0 2522
3

Or using the same method as the ASM answer above:

PHP, 103 bytes

for([,$c,$s]=$argv;$i<4;$l+=$r)if(2<$r=substr_count($s,$s[$i],++$i)){$l++;$c+=77;}echo$l+=$c+10*!$l>99;

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PHP, 89 84 bytes

foreach(count_chars($argv[2])as$a)$b+=[2=>1,3,7.77][$a];echo$argv[1]/100+($b?:.1)|0;

Try it online!

Input from command line, output to STDOUT:

$ php lucky.php 99 3333
8 

$ php lucky.php 0 2522
3

$ php lucky.php 0 abaa
3

Or using the same method as the ASM answer above:

PHP, 103 bytes

for([,$c,$s]=$argv;$i<4;$l+=$r)if(2<$r=substr_count($s,$s[$i],++$i)){$l++;$c+=77;}echo$l+=$c+10*!$l>99;

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