There's intangible values of a company: Goodwill, recognition (of logo, trading name)
THEN there's the tangible stuff: Machines, Vehicles, Telephone numbers, fliers, chemicals, property, contracts with customers.
If you're selling to someone who lives 100 miles away, then the intangible part is not going to be of much value, whereas someone in the same town it would be a massive value builder.
Also, are you a sole trader, or is it a Ltd. company?
As mentioned already, it's worth what someone will pay for it.