Paris is an expensive city but that doesn't mean that it is unaffordable. In fact, there are lots of free things to do and see. For comparisons of costs between Los Angeles or San Francisco and Paris, follow these links.
Comparison of costs in Los Angeles and Paris
Comparison of costs in San Francisco and Paris
The euro (plural euro) is the currency used in France, Germany, Italy, Spain, Belgium, and the Netherlands. It has been in use for over 20 years.
The euro is divided into 100 cents. The bills begin with the 5 euro note, then 10, 20, 50, 100 and 200 euro notes. Often you will have trouble spending larger than a 50 euro note.
You can get euro in the US from banks and money dealers, but the rate of exchange is usually poor so it is better to just obtain the cash from the ATMs which are all over Paris and even near the exit at the airport. Currently the rate of exchange is about $1.10 per euro. So $1.14 is about the most you’d want to pay for euro cash. Be sure your ATM and credit cards have a chip in them or they will not work in Paris. To take money from the teller machine, it is best to use a DEBIT card, not a credit card.
Rule of thumb: the best rate of exchange is usually obtained with your credit card simply by paying for purchases and meals with the credit card. If you want cash, use the DEBIT CARD. If the ATM offers to make the price in EURO or dollars, select EURO to save money.
American cash and travelers checks, etc. are just a nuisance to exchange in Paris as many bank branches do not have an exchange window anymore and when you locate a money dealer, such as near the train stations, you will pay a sometimes high fee for their services. Personal checks are useless in Paris.
Visa is the most widely accepted card in France; Mastercard is second; American Express is a distant third. Discover is unknown in France.
Do not exchange dollars for euro in shops, hotels, etc.
Apple Pay and Google Pay are now accepted in many French restaurants (especially casual restaurants and take-out places).
French prices include the sales tax (at about 20%). Thus if a sweater is marked 100 euro, about 20 euro is tax. Provided you are spending several hundred euro in one day in one store, the tax (called TVA) can be refunded to you when you take the purchases out of France. It’s probably best to concentrate your shopping in a department store, like the Galeries Lafayette, and do all the purchasing in ONE DAY, and get the forms and fill them out and have them STAMPED to obtain the refund. Then as you leave Europe at the airport, you must present the forms and mail the stamped forms back to the store from the airport.
Super fancy stores like Louis Vuitton or Hermès require you to buy a higher minimum amount to qualify for the refund. Inquire about the TVA refund in such stores.
Be sure to tell your family to never mail cash to you as it may disappear in the mail.