Use Egyptian pounds (EGP) for everyday spending. All monument ticket prices are set in Egyptian pounds, a low-volatility, official rule, so pounds are what you'll need at the gate even at sites that otherwise cater heavily to foreign visitors.
Cards, cash, and where each works
At the Giza pyramids specifically, self-service ticket machines accept bank cards directly — a rare exception to the general cash-first pattern at Egyptian monuments. Elsewhere, card acceptance is far from universal outside larger hotels and restaurants, so carrying enough EGP cash for markets, small vendors, and tips remains the practical default.
US dollars and euros are widely accepted for larger tourism payments — tour balances, tips, some entrance fees — and it's common to carry a mix: small-denomination dollars for tipping, EGP for daily spending. See How Much Should You Tip in Egypt? for how that mix is typically split.
Getting Egyptian pounds
ATMs are the most straightforward way to get EGP at a fair rate, widely available in Cairo, Luxor, Aswan, and other tourist centers — see What's the Best Way to Exchange Money in Egypt? for the full comparison against bank counters and airport exchange.