I want to change my iTunes Store from USA to Saudi Arabia, and I want to reset my balance

Buy something more expensive and pay the balance with a credit card or contact iTunes Support and ask them to zero balance your account.

iTunes Store - Contact Us - Official Apple Support.       

See al the requirements in the article below.

Region - Change your iTunes Store, iBooks Store, or App Store country or region.     

For the rules and support related to changing your county, see below. Be sure and use the support options if needed.

Change your Apple ID country or region https://support.apple.com/en-us/HT201389 See this heading especially What to do before you change your country or region.

Use this link in the document if you need to View your Apple ID balance https://support.apple.com/en-us/HT202359

If you can't complete any of the steps, can't change your country or region, or you have less store credit than the cost of a single item, contact Apple Support. As mentioned by Eric above, you could purchase something of value

greater than or equal to the amount of your store credit or ask iTunes Support to zero out your account balance using this iTunes Support Form https://support.apple.com/en-euro/itunes-contact

And you also can contact iTunes worldwide support via text or chat using this link https://support.apple.com/choose-country-region/itunes.

At the bottom of your screen, use Tell us how we can help to select among support options. You should be able to get telephone or chat support.