Auction Sites-Build Or Buy The Technology?

This not so, Anonymous Coward asks: "I am involved in a new Internet startup: a B2B Exchange. This will be an auction site where my commodity industry (based in Asia and Eastern Europe) gets together to buy and sell. The business premise is valid. My dilemma: "build or buy" the technology?" A not too uncommon question in the IT world, and one that greatly depends on your market and the resources you have available. Read on for more information...

"The technology is available to buy (everyone knows names like Ariba, Commerce One, Moai, etc., etc.). All great apps I am sure, but my impression (just an impression, so far I have not talked to the vendors!) is that these are just toolkits - that I would be paying half a million dollars to get some consultants for four months actually writing the app. And then I'd probably pay royalty fees, maintenance fees, etc.

The other option: build it ourselves. I could specify our requirements, then hire a team of programmers and tell them 'build it.' Advantages: quicker; more control; I can use open source technology; etc. Drawbacks: maybe we are re-inventing a wheel; and we do not benefit from other users' experience.

What do you all think? Is an auction mechanism doable by ourselves? Or are we, by doing that, just reinventing the wheel? Is auction technology mature yet to call it a "product"? Has anyone worked with these?

I'd highly value your opinion. Elsewhere I would just hear business hype."