Our local scheme charges £5 for membership, you can go every weekday and get 12 items for £4.
There’s a “pay it forward” scheme so that you can pay for someone’s membership or someone’s shopping anonymously. There are wooden pegs in the board next to the till with tickets that others have paid for, you just discretely take one. (The volunteers make sure there’s always at least two there)
They also have discounted “little extras” like milk and frozen goods, - which are bought in and sold at cost.
They use the money for rent of the room, fuel for collecting donations and to buy fresh food staples like potatoes and carrots and fruit depending on the quantity of donations they have.
Anyone can join, no proof needed, but it stops people taking too much too often. Occasionally if they have a lot of a perishable item, like cheese or bread, (last week it was spinach) it won’t count it towards your 12 items and you can take extra.
Everyone here feels the cost is very reasonable, especially with the “pay it forward” scheme.