Q: can i get money back for accidentily purchasing an app

no, sorry.  Apps cannot be returned.  But try to convince the iTunes App Store Support that you made a mistake, perhaps they will oblige.

In iTunes, open the Store menu, then "View Account".  Sign in with your AppleID, then open your Purchase History. At the bottom of the list with your Purchases is a "report a Problem" button.  Click it and describe, that you made the ia-app purchase accidentally and ask for a refund.

I doubt it via the Developer

https://wooga.helpshift.com/a/jelly-splash/?p=web&s=terms-of-service&f=terms-of- service

Try doing what léoniesuggested and contact Apple within your receipt.

Contact the App store support - and see if yoru credit card company will stop the charge

LN