under 100k per year in gross sales, the clients are worth nothing; the only value comes from fair market value of assets. 100-500k annually, 2-3 times EBITDA plus fair market value of assets. 500k+, 3-5 times EBITDA plus fair market value of assets.
Some segments of the industry simply have higher EBITDA and consequently higher valuations.
If this post seems mean, it's probably because I'm drunk posting. Maybe my next one will be better...