Lizzy here, I’m a Shopify support Guru.
Typically when you're seeing a price with a strike through like that, it means you have a "Compare At Price" set up within the product. You can check whether this is the case by going to the product page in the admin.
If you have variants, you made need to go into the bulk editor or variant pages to see the compare at price that has been set. To get to the bulk editor you can tick the checkboxes of the variants you'd like to edit then click "Open Bulk Editor".
In here you can add the field "Compare At Price" and remove any numbers that appear in the boxes.
Let me know if that helps to remove the double prices from your store.
I noticed you mentioned that you set your store up recently. How has it been going so far? Have you started any active marketing via social media or are you working on driving traffic to your site in other ways?