A carburetor averages about $380.00 new, rebuilding one takes 3 or 4 hours at best, $90/hr and a rebuild kit is about $35.00 ($50 dealer cost).
Today, the key related issues would be O2 sensor related ($80 DIY or $140 shop/dealer cost). It takes about 20 minutes to replace and test and you have brand new, electronic components, not a cleaned and reconditioned mechanical device that may or may not last.
With an older car with gummed up carb ports it's harder to determine the actual source of the issue too. I can easily see and record sensor output voltages, volumes etc. while driving and plugged into the OBDII system, before it was a lengthy visual inspection where you really had to understand the vehicle's engineering in order to pinpoint issues.
Unfortunately, the OBDII system also has drawbacks, mechanics will accept work on ANY car, as they all have the same base diagnostic systems but they are less likely to learn specific quirks.
I had a lady call me, 2005 Mercedes 320SEL, that had hired a mechanic from Craigslist. He called me in to scan it and give him details. I sent him step by step instructions straight from Mercedes, EASY stuff. He didn't connect the wiring harness son the part he installed, a $150 fog light fell out while she was driving home and scratched (mechanic wouldn't pay to replace it). Again she called me back, I went in, pulled it apart and connected the sensor, buffed out and polished the fog light and charged her dinner (she was a great cook, single and worked in music, I couldn't resist!).
And, while I am babbling, a good story (for me).
I bought a truck that had failed AirCare 3X's. Judging by the AirCare reports (you can actually punch in a VIN# and see all past AirCare test results for the vehicle, no cost)and the parts the dealer had put in it, they were chasing an issue of it running lean on one bank. They had replaced over $1500.00 JUST in 'wholesale' parts costs, including the catalytic converter and barely SCRAPED it through Air Care when it was spring time (having failed in September the previous winter).
I know that that particular truck had a problem with upper intake manifold O-Rings. When they get old they lose their seal, cold weather makes them brittle and it will suck in too much Air when cold, which is why they finally got it through when the weather warmed up.
So I bought it, O-rings cost $21.00 and took about 2 hrs to install myself, problem solved! SCORE. Everything else had been replaced, all 4 O2 sensors and a $400 MAF sensor included. Low mileage, second owner brand new everything.
Even funnier, the dealership could have just registered it as being over 5100lbs and skipped AirCare altogether! :D It weighs 4800lbs, with any occupants or gear in it, it will be over 5100 most of the time. Insurance is only SLIGHTLY more expensive but it would have saved a potential owner over $2500 in shop repairs anyway.
It's a funny field these days; if you find the right mechanic, he/she will be able to fix it and replace only the problem parts at a fraction of what it used to cost. When parts are replaced, there's no tuning needed, they tune themselves nowadays. The only issue is running into mechanics that think retrieving a system code will give them the right fix (which it usually doesn't)and it costs more as they will chase codes and replace numerous parts. :)