According to PriceOfTravel.com:
*all prices converted into US dollars in mid-November, 2010
Price ranges reflect shortest to longest rides in most cities. Tourists are most likely to pay the lowest price.
- Caracas, Venezuela (metro, bus) $0.12 – $0.28
- Cairo, Egypt (metro) $0.17
- Delhi, India (metro) $0.18 – $0.66
- La Paz, Bolivia (bus) $0.19 – $0.50
- Kuala Lumpur, Malaysia (light rail, bus) $0.22 – $0.76
- Marrakech, Morocco (bus) $0.24 – $0.61
- Mexico City, Mexico (metro) $0.24
- Panama City, Panama (bus) $0.25
- Quito, Ecuador (bus) $0.25 – $0.35
- Hong Kong, China (tram, ferry) $0.26 – $0.39
- Buenos Aires, Argentina (bus, subway) $0.28 – $0.32
- Beijing, China (subway) $0.30
- Dakar, Senegal (bus) $0.31
- Lima, Peru (bus) $0.36 – $0.64
- Auckland, New Zealand (bus, train) $0.38 – $1.38
- Macau, China (bus) $0.41 – $0.83
- Shanghai, China (metro) $0.45 – $1.35
- Cancun, Mexico (bus) $0.49
- Taipei, Taiwan (metro, bus) $0.49 – $2.14
- Bangkok, Thailand (skytrain, subway) $0.50 – $1.34
- Singapore, Singapore (subway, light rail) $0.61 – $1.53
- St. Petersburg, Russia (tram, bus, metro) $0.61 – $0.71
- Cartagena, Colombia (bus) $0.64 – $0.80
- Dubai, UAE (metro) $0.68 – $2.18
- Montevideo, Uruguay (bus) $0.76
- Sofia, Bulgaria (tram, bus, metro) $0.80
- Phuket, Thailand (bus) $0.83, $1.17
- Moscow, Russia (metro) $0.84
- Krakow, Poland (bus, tram) $0.86
- Seoul, South Korea (subway, bus) $0.89 – $1.77
- Prague, Czech Republic (tram, bus, metro) $1.00 – $1.44
- Santiago, Chile (metro, bus) $1.00 – $1.20
- Istanbul, Turkey (tram, bus, metro, ferry) $1.03
- Cape Town, South Africa (bus) $1.14
- Lisbon, Portugal (tram, bus, metro) $1.16 – $3.97
- New Orleans, USA (tram, bus) $1.25 – $1.50
- Rio de Janeiro, Brazil (metro, bus) $1.28 – $1.74
- Budapest, Hungary (tram, bus, metro) $1.28 – $2.32
- Athens, Greece (tram, bus, metro) $1.37
- Madrid, Spain (metro, bus) $1.37
- Monaco, Monaco (bus) $1.37
- Rome, Italy (tram, bus, metro) $1.37
- Tallinn, Estonia (bus, tram, trolley) $1.39 – $1.74
- Dubrovnik, Croatia (bus) $1.48 – $1.85
- Los Angeles, USA (bus, metro) $1.50
- Chicago, USA (metro, bus) $1.54 - $1.73
- Dublin, Ireland (tram, bus) $1.58 – $2.47
- Nice, France (bus) $1.58
- Tel Aviv, Israel (bus) $1.58
- Washington DC, USA (metro) $1.60 – $5.00
- Bruges, Belgium (bus) $1.64 - $2.74
I'll stop there, as they just get more expensive after that.
So according to this, Mexico City prices have gone up to US$0.24 now, so your best has now lost out to a few other cities, and now Caracas would probably take the prize.
