$re = '/(?:<span>Autogas[^]*)(?=[^]*<span ng-bind)([0-9.]{4})/';
$str = '<div class="fuel-price-entry" ng-controller="SpritsortenController" ng-init="init(\'0,659\')">
<div class="fuel-price-type"><span>Autogas</div>
<div class="price-box">
<div class="price-input" ng-class="{\'price-dirty\': dirty}">
<span ng-click="minus()" class="decrease-price">-</span><span class="price-field"><span ng-bind="display_preis">0.65 </span> <sup ng-bind="suffix">9</sup></span><span ng-click="plus()" class="increase-price">+</span>
</div>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php