Hey guys im trying to show our retail Price as additional information in the product details page.

{{#each model.item.matrixchilditems_detail}}
 {{custitem_rrpeur}} € <br />
{{/each}}

is there a way to sort the array from lowest to highest price ?

Outside of your specific problem, if you want to show RRP/MSRP, our recommended approach is to use the strike-through pricing functionality: https://docs.oracle.com/en/cloud/saas/netsuite/ns-online-help/section_159190992483.html