"How much is sugar?"
Translation:Sukari shilingi ngapi?
I'm think those two are interchangeable. Shilingi ngapi, Bei gani, and Pesa ngapi all mean "How much is" or "What is the cost of".
The only difference - which doesn't matter in this case - is that Pesa means "money" and Shilingi means shilling, which is the currency used in Uganda, Kenya, and Tanzania (Each have their own shilling).