I have a 2017 or 2018 Marin Hawk Hill. It has a cracked frame (see photo). My local bike shop contacted Marin, who said they have a frame that can be used. It would also require a shock replacement. The total, including labor, would be $750. I am wondering if it is worth it to do this or if I should instead buy a new bike. I don't want to spend a ton of money, so the replacement frame is appealing, but I also don't want to end up wasting money.
A new similar bike would cost ~1500 €/$/GBP, right? For half the price, you get a new frame, a new shock, all your old&used parts (in which conditions are they)?
No brainer: If you think your parts are worth at least 750$ and you can sell them for more than 750$, sell them and then buy a complete new bike.
If you think your parts are worth less than 750$, accept their offer (or find a better deal on a compatible set frame+fork)