For a family of four, SNAP maxes out at $668/month, or about $22/day, but averages $489/month, about $16.3/day for four people, or $4/day per person. Importantly, this is across the US, so those who live in lower cost of living areas do much better.
Families do better if their children are infants, as they also can get WIC, which helps them get highly nutritious food for babies.
By comparison it helps if you estimate your own daily food costs.
For about 7 months my family of 3 was receiving $526/month (17.50/day or 5.75/person/day) and I NEVER used that entire amount. There were months when I used less than half of the amount. Of course I took advantage of a little publicized benefit that goes with it - vegetable and herb seeds and plants can be purchased with SNAP benefits. I grew lots of veggies and then canned/preserved/froze. Selling much of that preserved home grown food stuffs was most of the income I was able to contribute to the household at that time, other than when my husband had a painting job that I could help with.
Of course I did that before I was utilizing SNAP and continued to do so after I stopped them.
By comparison it helps if you estimate your own daily food costs.
Which is something I have never done until having this conversation with you, so I did it and come up with an average of $200/month which works out to about $2.22 per day per person and believe me, we eat well.