Nethalus, have a look at a
Decathlon store for well priced bikes, or there is of course sites like Gumtree where you can snap some nice bargains up - though be careful of second hand, you don't want to pick up a lemon.
Here are some very handy websites:
http://www.parktool.com/repair/
http://www.sheldonbrown.com/
Between these two, everything to keep your bike happy and free rolling is contained. I would strongly recommend nipping out to Aldi / Lidl etc and picking up a set of allen keys, spanners and a screwdriver set for cheap.
Also remember to get a decent lock!
There are varying types of advise on locking your bike, Sheldon Brown has some good info on it. Personally if I were to chose only one lock I would go for a D-lock, and some lockable QR sqewers.
I would also recommend picking up a track pump - it will make keeping your tyres properly inflated a doddle, and that makes such a difference to the performance of your bike.
Clothing is also a big factor in comfort (I find, though I am a little wussy!) For anything over about 5miles I prefer to be wearing cycle shorts of some description. As prettyboytim said, a cycling jersey adds dramatically to comfort. I guess you can wear your bus drivers HV vest, but remember that if you wear a rucksack it will cover the vest, so an HV bag cover might be a good idea.
Finally, take Magnatom up on his offer of Cyclecraft - it will keep you safer than all the HV, lights, bells and helmets.