Where can I pick up a decent second hand bike?

Hi,
I am hoping to complete a triathlon at the end of the year, and also go on a couple of cycling holidays in the summer, so am looking for a bike that will be light enough that I could compete in a triathlon, but also durable enough (with room for bags!) for me to do a little bit of touring also. Im not a massive cyclist just yet so I just need something pretty decent to get me started.
The problem is, I dont have a load of money to be splashing out almost 拢1000 on a bike, so was wondering if anyone could advise me where I could pick up a cheap bike. A few people have said ebay is a good place to pick up cheap bikes, but Im always cautious about buying things from there. Does anyone know any places online or in London where I could pick up a suitable bike for cheap enough? Also, any pointers on what I should look out for, and what sort of price range Id be looking at would be greatly appreciated!
Thanks!

Go to bike shops and ask if they have taken any bikes in trade. There is nothing wrong with a used bike that's been checked out by a qualified technician. Also ask if they have any last year's models left over. Those are usually discounted pretty well to move them out of the store.

You should not have to spend 拢1,000 on a bike. You can get a new bike that does a good job of meeting the requirements you've specified for half that.

HTH

You sure dont need to spend a thousand, but you will be gald to spend a few hundred. Get one local off cragislist, where you can go and see the bike for yourself and pay in cash at the sellers home.

i bought some bikes from craigslist.com. i had an old 10 spd fuji i got for $25 USD it was old, heavy but shifted nicely and i used it in two triathlons and commuted with it for an entire summer (20k one way) dont llisten to these guys who say you gotta have a $1000 bike, i loved this bike. i used it to see if i would be interested n the sport. so this year, after three years of riding, i bought a nicer bike! good luck, hope it helps

I would look at Ebay and craigslistUK im always looking on ebay for old Colnago bikes and there are alot of bikes on there from the UK from almost new to very old. For a 1000 pounds you should try looking at a few bike shops for something new as well, 1000 GBP will get you a nice new road bike. As far as the bike you may have issues a bike suitable for a tri and throwing bike bags for a long tour may be a problem. I'd look for something like a regular road bike that you can add bags for long trips or aero bars for a tri. Steel would be best for long tours, but too heavy for a tri. An Aluminium bike has a harsh ride (dosen't absorb road vibe very well) not great for a long road ride. Check out something in titanium or carbon both are very versitile.

Try to get one ex-hire from a reputable bike shop