Here's an article listing the Top 5 Best Vintage Singer Models, and many people who collect and sew with vintage Singer machines do love and seek out these particular models.
The first machine for family use, Singer's new "Family" sewing machine, was manufactured from 1858-1861.
Therefore, the following dates can be considered to be "close".
These dates and the information in this table relied heavily on many others' research for which I am deeply indebted, as well as my own.
Actually, there are lots of variables to estimating the worth of an old sewing machine, so let's look at the most important; the make/model and date, the condition, and any extras that may be included with the machine.
There aren't any comprehensive lists for identifying models or manufacture dates for old BERNINA machines available online.