If you want to build a light weight bike on a budget, you have to keep track of every part to figure out upgrading which parts saves you the most weight for the least money. You should budget $10 for a cheap kitchen gram scale to verify weights as well.
I’ve done most of the hard work for you, and modified and simplified one of my personal spreadsheets for your use. Attached is a spreadsheet with two examples. One is an example build on a
$1,500 $1,400 budget that weighs 16 lbs with pedals and cages. The other is is an example of a sub-UCI build for less than $2,000 $1,900.
Many of these weights are list weights and unverified. A couple are best estimates for a size medium with a wheelset suitable for a fit medium size rider. These are just an example, using new and readily available parts. You can do much better if you get deals on used or clearance parts.
These builds do not use any Chinese carbon in any structural applications, only for the bottle cages. Chinese carbon is a contentious subject, and I won’t speak for or against it here, except that you should avoid falsely branded counterfeits at all cost.
The carbon components used in these builds comes from Nashbar, because quality control is ensured by an American company, and they are backed by an American company through Nashbar’s “Forever Guarantee” which is almost better than a life-time warranty.
At the bottom is a comparison to some off-the-shelf bikes. They are just for reference, no comparisons about the ride quality and so on are being made or implied. It is just a straight price and weight comparison for reference only.
Again, these are just example builds, there’s a blank template on the third page for your use.
Edit: Given the heavy reliance on Nashbar and eBay in the example builds, I figured I should plug Ebates. It’s free, and if you sign up for Ebates you can get 3.5% cash back on Nashbar/Performance Bike purchases, 4% off Backcountry/Competitive Cyclist, 1-5% off eBay (rates fluctuate, but at least 1% on sporting goods), 1% off of some of the UK based shops, as well as a a $10 bonus after spending $25 at any of those places. In my experience this is cumulative with coupons, sales and eBay bucks, and they send you a check in the mail or via paypal. That’s about $50 off the example sub-UCI build, and about $25 off the 16 lb $1,500 build making it $1,400.