I requested new piping under my sink as well as unclogging services. Both were quoted to me as a fixed price. The piping was done very quickly, but the project went sideways with the clog, as the original plumbers who built my house did a very poor job in its construction, causing a lot of issues.
Despite it taking Tornado plumbing almost 2 hours to unclog my kitchen drain, they still charged me the same price, and at a significantly lower price than other places I asked for quotes.
The best part is that they are unbelievably nice, explained the process, what the problem with the piping is (and why we need to replace it), etc. etc. I'm glad I found them because now they're my go-to plumbers.