Guides
The money-and-sanity-saving stuff, written to be the best answer on the internet.
Money
Splitting money on a group trip
Split accommodation and transport evenly, itemise food and drink, settle once at the end.
Paying abroad: cards, cash and the conversion trap
Always pay in the local currency — accepting 'pay in EUR' hands the merchant a 3–7% margin.
City taxes and tourist fees
City tax is per person per night, excluded from your quoted rate, and often cash at check-in.