Budapest is not a huge city, but it is quite large and it's easy to lose your way if this is your first time. If you will not have net access you should get an offline map app and make sure you download Budapest. (Btw CDMA phones will not work on Budapest. You can check your phone here: www.frequencycheck.com)
Of course the most important issue is to get from the airport to your hotel. There are two viable options.
Taxi. They are fixed price, and quite expensive. Good for shared transport if you travel with others.
Bus. Budapest public transport (BKK) requires a new ticket for each vehicle you use. So at each change you need to validate a new ticket (350 Huf). Unless you have exact change (very unlikely) you must buy a ticket at one of the BKK offices. A much better option is to buy a weekly/half month pass for 5000/6300 Huf, unless you plan to do almost everything on foot.
You can buy the passes at BKK offices at the airport. They have one at both terminals. You can also buy at ticket machines. Both the office and the machines take cards, no need for cash.
If you are staying at the Ibis Budapest Centrum, here are google directions and map.
The exchange booths are safe and give very good rates for USD, EUR, CHF and GBP (not so good for minor/exotic currencies.) Here's a link to find the best rate near you in Budapest: http://www.valutacentrum.hu
Also American Express is rarely excepted, it's missing from the list is not a typo.
Hungary still runs on the Forint (HUF). Bank notes are printed in denominations of 500, 1000, 2000, 5000, 10000, and 20000 HUF. Hotels usually accept USD and EUR. For the exchange rate see www.xe.com. Major credit cards (VISA, Master Card, EuroCard) are usually accepted (in hotels, restaurants, and in most grocery stores). Banks are generally open 8:00 am to 4:00 pm Monday through Thursday, and 8:00 am to 1:00 pm on Friday. All banks are closed on weekends and public holidays. However, there are plenty of currency exchange booths around downtown. ATMs are widely accessible and tend to accept most US bank cards (and give you Forints or Euro). Common wisdom holds that your safest and most economical way to get cash is by withdrawing from your bank account at an ATM.
Participants can book rooms at discounted rates at the Ibis Budapest Centrum with this booking form. The deadline for reservations is May 24. As the booking form says, after this date "the hotel reserves the right to confirm the booking upon the availability of the rooms".
Participants can also book fancier rooms at Hotel Museum Budapest, for 85 euros/night for a single room, or 95 euros/night for double/twin rooms, with breakfast included. There are 4 rooms held for our participants, and the discounted prices and free cancellation are valid until June 14. There are no booking forms here, but mentioning the event (or perhaps contacting sales1@museumhotel.hu) should work.
Alfréd Rényi Institute of Mathematics, Budapest
9 - 14 July 2018
16 - 20 July 2018
Jim Brown Gergely Harcos Jay Jorgenson Árpád Tóth Lynne Walling