Well, the next sentence explains. Basically, if you are that badly off that spending 3 bucks for pop tarts is a splurge, either that's the only thing you splur

Well, the next sentence explains. Basically, if you are that badly off that spending 3 bucks for pop tarts is a splurge, either that's the only thing you splurge on or you buy something more economical. With some hyperbole used, buying a pop tart or equivalent when you're poor is like buying soda when you're poor. You either sacrifice for it, or you use something cheaper that does roughly the same thing (water), or you go without.