PHP or Javascript Custom Field Data Formatting

I need some custom code work to take custom field data and reformat to a format that a third party finance calculator will accept and use.

eg Pricing Custom Field shows 9,995 on the website but the value needs to be 9995 for the calculator and generated per post. another example is date custom field comes in as 20201024 but needs to be 2020-10-24.

All custom fields are filled from an imported XML that we can not change at the source.