http://www.acmqueue.com/modules.php?name=Content&pa=showpage&pid=143
if your company is unwilling to spend on a search appliance, then it must be willing to spend a long time building an inferior, not-so-reliable, less performant custom solution. Well, there is no stopping you from designing and carving your own snowboard, bindings, and boots. Me, I'd just go shopping for some quality ones that allow me enjoy the ride over powder.
That said, your fastest bet is to look at SQL Server Full-text Search to perform the indexing for you. It is a fairly straightforward and I got it working the way we needed for our project within a day. That actually means it is not very feature-rich; I still find it lacking for some advanced (but common) situations, but for simple operations it will save your hide.
The melody of logic will always play out the truth. ~ Narumi Ayumu, Spiral