Lotus was an American marketing company that had their bicycles contract manufactured in Asia by various companies including Tsunoda (Japan), Yamaguchi (Japan) and Pacific (Taiwan). They were considered good value and the line covered the full range from entry level up to professional level.
The subject bicycle appears to be a mid-range from the early 1980s. However, to give an accurate appraisal we would require more information. Pictures and/or brands and models of the major components (derailleurs, cranksets, brakes ) would be a big help, as would pics/type of tubing decal. It appears to be Tange but I can't make it out. An overall picture taken from the drive side would also help in assessing overall condition. Finally, your location would be a big help, as prices can vary considerably from market to market.
Edit: Oops looks like |I was composing while daf1009 was posting. Sorry for the doubling of requested information.