When you sell a business of this size it is no longer 3 times, 4 times or whay ever times the monthly value.
A business with a turnover of 120k plus like this one will be valued on its profit for the month and may be a bit of good will thrown in.
You may get anywhere up to 10k and 20k if your lucky.
If somebody had 80k to spend it would be better for them to live off 30k of it and spend the year building up a business of there own.
Spliting the work would be the best way to maximise monies made by selling.
Hope this helps.