I did a 6" long repair in a soft nylon looped pile carpet on Saturday and charged the people $125. The vacuum cleaner pulled a yarn out. I wasn't even sure I wanted to attempt it because of the carpet type and location it was in the room. I mocked up and did a test repair using a remnant piece. That turned out good, so I did the actual repair. Turned out invisible and I know the repair will be bullet proof. Replacing a single row in this soft carpet felt like I was doing surgery. Trimming and sealing all the cut edges without weakening adjoining rows or getting any hot glue on the carpet pile went real slow, so I charged for it. Using the long narrow tip I made a few years ago, I was able to seal the trimmed edges of the main carpet, then sealed the edges of the repair row. I nuked the repair using the Koolglide iron.
$125 is my minimum depending on the time I spend and what's involved. I don't charge $125 to install a carpet door metal. Had the repair turned out so-so, I would have reduced my price being it was a repair. It turned out fantastic so I held my head high.