How to check if my specific prices are correctly exported?

First check that the discount is active and applies to the product in the feed context: country, currency, customer group, taxes, quantity and dates. Do not expect a specific price in the XML if it does not apply in that context.

1. Regenerate the feed or open its on-the-fly output in My feeds.
2. Find the product or combination ID and compare its price fields.
3. When a discounted price applies, the module writes the reference price in g:price and the discounted price in g:sale_price.
4. Open the same item's product URL in the same currency and a comparable context. Then check Meta's latest retrieval.

Fictitious example: a EUR 20.00 product with a 20% discount produces:

<g:price>20.00 EUR</g:price>
<g:sale_price>16.00 EUR</g:sale_price>

The feed and storefront must remain consistent. See price discrepancies, data comparison and update frequency.