Apart from your flights and hotel room, you'll be hard pressed to spend money in Luxor, unless you allow yourself to be ripped off or wish to buy pashminas and replica relics. Everyone will try to help you with everything, including pointing at something for your to photograph and then ask you for money for what they did, be firm and polite and say no.
A taxi from the airport is LE 80, around £4, ask and confirm the price before you do anything and check it's LE (Egyptian Pounds) and not $ (Dollars).
Expect to pay up to LE 700 per person for a full day tour of the West Bank, to include the Valley of the Kings, a couple of temples and the tour guides, brothers, Alabaster or Papayas shop. You will have to pay extra to visit Tutankhamen. You can however do this cheaper yourself, but I'd recommend a tour guide a) to tell you the history b) to stop you being hassled and c) to get
you back to your hotel.
You have to pay your hotel bill in foreign currency, you are not allowed to pay in Egyptian Pounds, but you can withdraw local currency from the cash machines. Banks are heavily guarded, but don't let anyone try to assist you and preferably withdraw money in pairs.
No one will have change anywhere, and will delay giving you change in the hope you won't bother waiting.
Don't bring kids with you unless you are prepared to keep a very close eye on them 24/7 and entertain them yourself. While the hotels have pools, they are a long way from the rooms, terraces, life guards are rare. There are no facilities in Luxor aimed at entertaining children, whilst there is a MacDonalds, there isn't a play area, there are no swings and slides to be found or public parks and internet is scarce.
Use the Internet.
Leave that laptop at home. There is little if no wifi in public places and in the hotels, you are limited to two devices per room. Wifi is often limited each day and costs around $10 per 250mb. Your mobile phone provider will sms on arrival with cost of calls, but if you wish to buy a sim card, you can only get this at the airport.
Drink the water
December and January are the height of the tourist season, but don't expect to have to wait in long queues for anywhere, there are sadly few tourists coming to Luxor since 2011, due to the current political climate.
Luxor is a relaxing place to visit, tours start early morning, 3 days minimum stay to visit all the sights, take a trip on the nile, fit in a hot air balloon trip and enjoy leisurely drinks and meals in the hotel.
Relax with personal safety
There are many warnings about travelling to Luxor and Egypt in general. The biggest risk is around mosques at prayer times and if you see large groups of people forming, then it is advised to leave the area and not hang around to see what is going on. Use the hotel safe for your passports, laptops, etc and only carry with you cash and cards that you think you'll need each day. Keep your bag in full sight at all times.