Quick answer: Kyoto runs about EUR 110 per day mid-range - noticeably less if you eat local and walk. Cheapest window: March–April (cherry blossom) or November (autumn colors).
What things actually cost
convenience store onigiri
1.00 EUR
bowl of ramen
7 EUR
city bus flat fare
1.50 EUR
temple entry
3-6 EUR
matcha latte
3.50 EUR
coin locker at Kyoto Station
3 EUR
Eat well for little
Ramen at Honke Daiichi-Asahi near Kyoto Station - rich shoyu bowl for about 7 EUR, expect a queue
Nishiki Market grazing - skewers, tamagoyaki and pickles at 2-4 EUR per stall snack
Yudofu (simmered tofu) near Nanzen-ji - Kyoto's temple cuisine classic, sets from about 15 EUR
Obanzai set lunch - home-style Kyoto small plates at downtown counters for 10-14 EUR
Matcha parfait in a Gion tearoom - about 8 EUR, Uji matcha is the local standard
Money mistakes to avoid
Cramming six temples into one day - pick two or three; temple fatigue is real and each needs slow time
Visiting Fushimi Inari at midday - the gates are packed; go before 08:00 or after sunset when they are nearly empty
Relying on cards - many small restaurants, temples and shops are still cash only, keep 10,000-20,000 yen on you
Photographing geiko and maiko on Gion's private lanes - it is banned and fined; watch respectfully from public streets
Transport without the tourist tax
From Kansai Airport the Haruka express reaches Kyoto Station in about 80 minutes (around 20-25 EUR with the Icoca and Haruka discount). In town use an IC card on buses (flat fare about 1.50 EUR) and the two subway lines; walking plus the occasional bus covers most sights.