It depends on whether the grocery store accepts Bitcoin as a form of payment. While some merchants may accept Bitcoin, it is still not widely accepted as a form of payment for everyday purchases.
In addition, even if the grocery store accepts Bitcoin, you would need to transfer your BTC from your Netcoins exchange to your personal wallet, and then use that wallet to make the purchase.
It is important to note that using Bitcoin for everyday purchases may not always be practical due to its high transaction fees and potential for price volatility. You may want to consider converting your Bitcoin to fiat currency, such as US dollars, before using it for day-to-day expenses.