You can use cheaper or older shoes for training, and you don't need to train 80k/week for the whole year if you are running two marathons. I'd say you can do it

You can use cheaper or older shoes for training, and you don't need to train 80k/week for the whole year if you are running two marathons. I'd say you can do it a lot cheaper than 1k if that's what's important to you.