I wouldn't get it. For a bike with a few thousand miles with Tiagra and Sora components, that's a little too much.

Actually, after looking again, it comes with a ton of stuff, and it looks like you'd get everything you'd need to ride. I wouldn't pay much more than 400, but with all the extras, it might be worth it. The only problem is you don't know how it will fit, and you especially don't know how the shoes will fit. It seems like a reasonable price, but it's definitely not the steal of the century, so I wouldn't worry about passing it up and not finding anything else.

If I were you, I'd check out craigslist and see if you can find something there. That way, you'll get to try the bike first, and see it and what not, plus you won't have to pay shipping or tax or anything. Just my $0.02. If you do decide to go with ebay, there will be plenty more like this one.

Oh, and if that's your bike and you're just posting to get more traffic, then shame on you.

I agree that's it's probably a little high. Even with the extras. At that price point I'd like to either see something with better components or a few less years.

And never buy a used helmet. Yikes.

Would the bike work for tri's? Absolutely. Any distance you'd likely be fine on that bike or something similar. Trek makes a good product.

Can you replace components as necessary, absolutely. But be warned that can be a slippery slope. Start replacing components on a bike of that level and you've quickly surpassed a few the price and level of the frame.

But there is one thing to consider. Going from a hybrid to a road bike is a big change. I'd go to a few local shops and see what's in stock to find a good fit. Talk to the shop people and get their opinion on what might be the best option based on use and your body type. May find a deal or two left over from last year as well. I think looking used at $400 you're not far off from an entry level bike off the shelf.

For a first bike, I'd probably try to avoid ebay. The biggest thing with buying a new bike is how it fits you. The best thing to do as you start shopping is to find a place that can do a basic fit for you, or let you try some bikes.

Tell them your price range and be honest (if it is your local shop having a great relationship with them is a good thing). They will probably be happy to help you, knowing that you'll go there for little things and maintenance and spread the word about their shop. Plus there is always the chance they'll find you a bike you just have to have :)

If you really have to end up finding a different (ie cheaper or used) way to get a bike, at least you'll be more confident in what size to look for. And some bikes will be able to help you find someone who is selling something that might be right for you, or some have used bikes.

I have bought all my bikes on ebay. I have sold a lot there too. However, I agree with the above posters. This is a little high for this type of bike. If you know your size, have done your research, and set a top price that you are willing to spend for a particular bike, you can get a good deal. Don't get your heart set on one and get carried away with the bidding. I would look into a tri specific bike if I were you.
Watch ebay though. It is a site for scammers. If the deal looks too good to be true, it is. If someone wants you to send them a cashiers check outside of the ebay system dont. Look at the history of the seller. See if they sell bikes or by bike related stuff. Sometimes the account is highjacked by someone. If the seller has a history of being a beenie baby dealer, think twice.