As a seller you may not know that much about the buyer's BATNA - in particular, are they looking for "my product or something like it" or are they looking for "a solid product with customers and a seller unable/unwilling to grow it."

They may be fully willing to walk away and in many cases probably will, because if they were THAT gung-ho about competing in your niche market there's a good chance they'd already be involved with something competing with you and much more likely to decide to just build it themselves.

Actually having more than a nominal number of paying customers is also a huge factor - how long did it take codetree to get those customers? Add customer acquisition time to your development time estimates.

From the seller's perspective you've got to have a buyer and buyers at this price point buy on a multiple of SDE vs. development cost. If dev cost is greater than what buyers will pay then as the seller... you're probably going to have to eat it and take less.

Importantly as the buyer a big part of what you're buying is customers that you can talk to and work with vs. just the code. If we thought Codetree would have taken twice as long to build but had zero customers we wouldn't have bought it at half the price. Having paying customers proves that you've bought something that other people value. Buying code just gets you code and you may find out that no one will ever pay to use it.