I suspect you’re overthinking things…
Whatever you normally spend your money on, put it on your credit card. In the unlikely event that they charge a credit card surcharge, pay some other way.
If you’re close to reaching the cut-off date for spending the $3000 you need to spend, and you haven’t quite spent enough, then you could start thinking about buying gift cards.
Credit cards are great … just make sure you pay off the total in full, every month, to avoid being charged interest.
All the best!