Hi!
I am going straight to your question about complexity.
Because the target site is an asp one, we need to be extra careful to perform the postbacks in teh expected manner, when emulating a visitor search perfomed withing a browser programmatically, so the complexity is up a bit from a plain web load and parsing the returned HTML for the desired data. That is true regardless of what programming language and techniques are used to accomplish the data gathering part. And that extra complexity and need for carefulness would account to about one forth to one third of teh final cost.
Now, lets assume it's all programmed withing the confinements of MS Excel using its programming capabilities(Internal Visual Basic for Application parser) there would be no extra expenses for software and licences for commercial use of tools and elements. If wutten as a desctop compiled program that would certainly not be true.
Now, if it will all run within Excel, there's important questions you need to answer:
A) Version of MS Excel and
B) OS - it would run on Windows or Mac
on the final place where you would be running this at. Those are important because VBA capabilities and tools differe from version to version, and teh second one is very important because, although Microsoft had indeed put forward, and supported, Office versions for Mac for quite a while now, the Mac VBA is VERY limited compared to the Windows.
The two days would be enough for all, including testing.
Kind Regards,
Dobri