Compared to where ? $2 isn't even worth the same, depending of the place you are in the US.
I know because I spent 5 months cycling through the US on a tiny budget.
For calories you would buy ramen noodles. Aim for 2000 calories per day or more. For Vitamins and fibre, buy apples ($1.11 per pound). At least one apple per day. An iceberg lettuce every 10 days or so is a good idea.
What does that average to ? Maybe $5 a day ??
Won't go very far anywhere in the US, but it'll go a bit further around Canton, MS than it will in Houston, TX. But yeah, you're screwed either way.