Deuteronomy 4:15 (snip):
וְנִשְׁמַרְתֶּ֥ם מְאֹ֖ד לְנַפְשֹׁתֵיכֶ֑ם
"Watch your lives very much"
The commentary Ha'emek Davar, among others says that this verse teaches us that we are obligated to watch our bodies and prevent it from danger.
Let's say someone is car shopping. He has a certain budget. Halachically, in keeping with this law, if one car has more safety features such as more air bags, better NHTSA (National Highway Traffic Safety Association) ratings, and is, overall, considered a safer car than another, is one obligated to spend more money to get the safer car?
What if it is the same money (approximately) but the safer car doesn't have the comfort or features that you want? Must you still buy the safer one to fulfill this mitzvah?
I am using the car buying as an example, but, no doubt this could apply to any purchase situation of any product. What extent must one go out of his way when purchasing something to fulfill this mitzvah?