I for one would like to know where nice Jensen 75 is for sale for $100??
There is a #75 just listed with a starting bid of $70.00 probably go for a bit over $100 , but who knows ? Looks to be in better than overage condition.
Nice earlier one too, respray the corroded brickwork with some stove paint and you’ll have a very good engine. Try offering $85 before it gets any bids 
Good advice , works for me occasionally👍