Is a International worth anything? It is in a cabinet,knee operation. I found one for 35.00 but don't know anything about them. Also are old Kenmores worth anything in cabinets?

Depends on how "old". Starting early 1960s the manufacturers started putting nylon and plastic gears in sewing machines, and when they wore out, it would cost more to replace the old gears than the machine was worth.

If you are talking pre-1960 machines, they are most likely all steel mechanicals, and yes, they are worth fixing up if not too far gone. A rusted solid boat anchor is not worth it...unless an extremely rare machine...very antique. Anyway, $35 is good for a machine is reasonable working condition..not perfect, but not frozen up. In general, machines are worth what someone will pay for it. International was probably a name put on by one of the major manufacturers for marketing reasons. How old is that one?

anything can have value- if it's what you want- value is relative-
if you are in the market for a vintage machine you need to set a budget---what it's worth to you- and the conditions---it has to be running- or it has to be (fixable) what ever---then look until you find what fits into your (ideal)
some people will pay a whole lot for an old vintage machine- some won't---it is all a personal choice-
you should start with looking up the specific machine you are considering- check ebay and places like that to see if anyone is selling them- and what they are (trying) to get for them-
check vintage machine shops-
check antique shops-
a singer featherweight can go for anywhere from $25===right on up to $500+...it all depends on what it is worth to you.

If you or someone you know needs a good reliable machine, then spending under $50 is a really good deal, if the machine is working or could easily be made to work. I have fixed up a few for friends and the old machines are easy to clean and oil and can sew just about anything because of their all metal construction.