What Country are you in? www.rswww.com or http://uk.farnell.com are a good starting point for pricing in the UK. Although I wouldn't use them for mass production.
I'm in Canada, the price for 1000 would be nice, but the list price for 1 also. Is there a general rule of thumb here? like listed price could be divided by 2 if quantity reaches 1000..?
Not really, it depends entirely upon what parts you are using. The more specialist a part is, the less of a price reduction you will get on it if you buy in quantity. Besides, you can't cost a product based on a rule of thumb... thats how you lose money!
BOM's get very complex as soon as you start dealing with non-generic parts. Speed/temperature ratings, package types, and now there's the whole RoHS mess floating around.
Also unless you've tailored your parts for a particular distributor, you're likely to have to go to multiple distributors, each with their own particular part number. Things get even more fun if you don't want to wait for x weeks of leadtime.
There used to be a couple companies in the dot-com boom that focused on doing the BOM thing, I think https://www.partminer.com/ is one of the few ones left standing. I've never used them, and I think they require $ to do anything useful.
Personally I just manually specify the distributors and let my assembly house (which I trust for this stuff) handle most of the pricing details - for small quantity projects, assembly cost is going to be in the same ballpark as the actual parts cost.
mouser's "My Mouser" and their project manager are great. it makes it really easy to spec out a bom for a project and then you just order 1000 of that project to see what the price breaks are. no need to complete the order so it doesn't cost.