TANF and SNAP are very different than what I am discussing. That are wealth transfers from general taxes to those in need. Very different than wanking into a public grocery store and seeing different prices based on your income.
Where I am, most grocery stores have two prices for items on the shelves. One "regular" price, and a second, lower price that only applies if one is paying with SNAP.
That taken to an extreme, this idea is the same as "from everyone according to their ability, to everyone according to their needs". Which sounds great, until you realize that this incentivizes needs and disincentivizes abilities.
Well, programs like TANF and SNAP exist, which I think are great and their greatest problems are they are not easy enough for people to make use of.
So, fair point, when looking at the most impoverished among us I do not think we should stop at governmental services.