CON'T FROM COMMENTS EARLIER. However, the installation took less than 3/4/ hour and was a basic regulator with no other function. Looking up the price afterwards, invoice did not list type or price, it appears that it would have cost me around $60 for the regulator and another $15 or so for the additional supplies necessary to install it and it was really a rather simple job with easy access. Given that, it seems that $300 for less that an hours worth of on site work, company says it does not include commute time in its prices, is a little high. While flat rate quotes are nice, they must take into consideration situations where the work load differs depending on the circumstances. Therefore, unless you are at the upper end of the harder work needed than the average job. it can be argued that my estimated price of $300 for labor was more than a little high. Maybe I am wrong since I have not used their services for years and am not knowledgeable of the costs of equipment and professional labor today.
The word "plumber" dates from the Roman Empire. The Latin for lead is plumbum. Roman roofs used lead in conduits and drain pipes and some were also covered with lead, lead was also used for piping and for making baths. In medieval times anyone who worked with lead was referred to as a plumber as can be seen from an extract of workmen fixing a roof in Westminster Palace and were referred to as plumbers "To Gilbert de Westminster, plumber, working about the roof of the pantry of the little hall, covering it with lead, and about various defects in the roof of the little hall". Thus a person with expertise in working with lead was first known as a Plumbarius which was later shortened to plumber.