The lari, cards and cash.
Georgia's currency is the lari (GEL), divided into 100 tetri. Some prices, especially for accommodation and tours, may be quoted in US dollars or euros, but payment is made in lari.
Cards are widely accepted in Tbilisi, Batumi and other cities, and ATMs are easy to find there. Outside the larger towns there may be no ATM, and smaller guesthouses, markets and drivers often expect cash. Withdraw enough before heading into the mountains or rural areas.
SIM cards and eSIMs.
A local SIM or eSIM is useful for maps, ride-hailing apps and keeping in touch on mountain trips. The main operators, Magti, Silknet and Cellfie, sell prepaid packages, and Magti offers tourist packages at Tbilisi and Kutaisi airports. Check each operator's site for current packages and eSIM options.
Coverage is good in towns and along main roads but can be patchy in remote valleys. Download offline maps before a mountain day.
Tipping.
Check the bill before tipping in restaurants, because some add a service charge. Where none has been added, leaving a little extra for good service is appreciated but not expected in the way it is in some countries. For guides and drivers on a long day, a tip is a welcome thank-you.