One in the very beginning of the show, when Walter’s old friend Elliott offers him a job at his company (that Walter originally created with him, but later quit, and then it ended up turning into a very successful business afterwards). With the explicit mention of their health insurance being able to cover all the costs of his treatment.
Then later in the show, Elliott and his wife straight up offered him money to cover everything, feeling that Walter deserves it (not in the least part, for being an original cofounder who was unlucky and quit right before the company got big).
There were more moments like those that i keep forgetting, but claiming that Walter started manufacturing drugs as some last resort to cover his medical bills is complete revisionism.