Are you talking about this app?
If so, yes see:
Video Star Pro Subscription
- A Pro subscription provides unlimited access to ALL current and future Power Packs in Video Star
- Payment will be charged to iTunes Account at confirmation of purchase, taxes may also be included in some areas
- Subscription automatically renews unless auto-renew is turned off at least 24-hours before the end of the current period
- Subscriptions may be managed by the user and auto-renewal may be turned off by going to the user's Account Settings after purchase
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Where to buy a physical Apple Gift Card or App Store & iTunes gift card: actually, you can buy an Apple gift card at many places, at an Apple Store or an Apple Authorized Reseller in your region.
See -> How to redeem your Apple Gift Card or App Store & iTunes gift card
How to redeem your Apple Gift Card or App Store & iTunes gift card – Apple Support (UK)
See also -> What you can buy with your Apple Gift Card or Apple Account balance
What you can buy with your Apple Gift Card or Apple Account balance – Apple Support (UK)
and ⤵️
- You can't use your Apple Account balance to send gifts or gift cards.
- If you use Family Sharing, your family members can't spend your Apple Account balance. Funds that you add to your Apple Account balance are only available to you. Find out more about how purchases are billed to your Apple Account balance.
- Some purchases might require you to have a credit card on file, even if you use your Apple Account balance to make the purchase.
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See also this Apple article: If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card
If you can't redeem your Apple Gift Card or App Store & iTunes Gift Card - Apple Support
Beware of -> About Gift Card Scams -> About Gift Card Scams - Official Apple Support
If you still need help, get support from Apple directly -> Get Support or call Apple in your region see -> Contact Apple for support and service or check -> here for more support and assistance.