Look at the numbers. The project is worth a minimum of 3x the annual gross (NOT EBITDA or net). If it is increasing in sales volume, margins are 40% or better, and it's truly scalable, it's worth closer to 10x to 20x. If the buyer sees it as a strategic purchase, not a tactical purchase, it can be worth as much as 100x.
Consider your unvarnished answers (no rose colored glasses, please) before responding with an acceptance, a counter offer, or a gracious decline.
Absolute genuis, @rohitkumar. Thinking back to the famous Betamax vs VHS tape technology, it wasn't the best tech that won, it was the easiest to implement. Websites/platforms are the same: the winners will be have the most elegant front facing solutions (graphics, ease of use, marketing/promotion as you note) not necessarily the most elegant back end or process solution.
Consider your unvarnished answers (no rose colored glasses, please) before responding with an acceptance, a counter offer, or a gracious decline.