2-3 million products, fulltext search

Hi all,

I'm starting a new project, an e-commerce website that has about 2-3 million products.

A quick rundown on the specs are
1) Products have 2 photographs.
2) Products have around 3-8 categories, 2-3 Specification attributes
3) The searchable description for each product has around 2000 chars.
You should be able to search within one or more categories.

Any suggestions ? My budget for running this is around 250-300$ per month. I have access to a Solr Server,

If you have any links to websites with a large volume of products and you know the system setup + backend specs, please share.

It's not clear, what exactly do you want to know: server specs or how to improve OpenCart search for huge number of products.