I've been car-free and traveling by a combination of bike and public transport for the last five years. My commute is 12 miles round-trip, which adds up to about an hour a day when I bike the whole way. I'm traveling mostly on city roads, with a few stretches on sidewalks. It also gets dark here in the winter (and icy -- which is why I sometimes take the bus).
The follow is the equipment I use and approximately what it cost (in US dolalrs):
1) Helmet: $20
2) U-lock: $20
3) Front and rear light set: $15
4) Regular-size bike pump: $10
5) White lightening chain lube: $5/bottle (I use 3-4 bottles a year)
6) Bicycle basket: $30
I probably spend $60-70/year on bicycle maintenance, but I let the shop where I bought the bike take care of that. They have a policy that people for whom a bike is their only vehicle get moved to the front of the queue, so I always get same-day service. I actually chose to buy from that particular shop, because I knew it would be easy to walk there if I had a problem. My situation may be different than yours in that I'm rarely more than two miles from a repair shop anywhere I travel (my city puts out a bike map with all the repair places clearly marked), so if I get a flat I can just walk somewhere and get it fixed. That's why I don't bother with a tire kit. And if my tires need extra air, all the shops let you pump up for free. So someone else will have to help you with those things.
Accidents aren't inevitable, but they're always possible. I slipped on some ice walking to the bus stop one morning this winter and ended up having to wear a wrist-brace for a month. I still got up the next morning and walked to the bus, though. And I was much happier walking (and am always tremendously happier biking!) than driving in a car.
My advice re:public transportation is to transition gradually. I two-hour commute is a big undertaking, especially if you have to do it every day. I kept my bus pass for the first two years I biked, and once I got the hang of negotiating heat/sun/traffic/rain/wind/snow/fatigue/etc, I switched to paying by the trip instead of getting the monthly pass. The only conditions I won't bike in are pouring thunderstorms, because I'm afraid cars won't see me, and severely icy conditions. Pittsburgh is a city of hills and the salt trucks aren't always that reliable. I can't handle a certain amount of excitement in my life, but hitting black ice on a bike on a high-traffic road is just too much.
But you probably don't get much ice in Australia, do you? Anyway, I'm super excited that you're thinking about biking! Honestly, it's one of the best things that's ever happened to me. I feel like my life gets better by the mile. Best of luck to you!
