If you don't use the car all the time and you're patient, not too muddled and clumsy, and just a little bit mechanically minded, I reckon you could refurbish your own carbs yourself. At home, with minimal expenditure on parts and tools, and lots of helpful advice from the people on here who helped me do the same. At first I was scared to have a go myself, but after some trial and error I got mine working pretty well, improved at any rate, and it was extremely satisfying. In my case I just used new seals and gaskets throughout and gave everything a thorough clean. I had the exploded diagrams from the workshop manual and parts book to refer to, and the refurb kit wasn't too expensive and came quite promptly. Couple of spanners and screwdrivers, strong coffee, jobs a good 'un!
Actually I bet the search function on here will show up lots of helpful photos and discussions from years gone by about how to do this.