1. Guild Tax
This is a very simple procedure. A weekly tax is payed to the guild bank, with this money the guild bank buys all kinda flasks, food and that kinda of material needed for raiding. This can be either raw materials which someone of the guild with then make into flasks or food or, as said, ready made of the Auction House.
The weekly tax is made by anyone Active Raider and up. By paying the guild tax you will get your flasks and specific foods for free, fishies are always put down.
Initiates do not, but can if they want stuff for free, have to pay the guild tax. Though they will have to get their own flasks or buy them from the guild bank for 75% of the Auction House price
The tax would be put at 50 Gold Per Week, this is equal to doing 4 dailies a week.
2. Donation of raw materials.
Donation of raw materials simply means that everyone, again Active Raider and up, makes a weekly deposit of raw materials into the bank.
Fish, Meat, Herbs. The log will then show who deposited that week and how much. Thinks like Chilled Meat of course do not count as they are not used to make anything. Rare Fish and Meats, Frost Lotuses. Generally I'd say check wowhead.com for the mats for your pots/flask/food and deposit those in the bank.
3. Bank takes all, gives all
This will basically mean. each and every Pattern, BoE (Epic, Blue) and Greens (For d/e mats), Drops like Veins, Herbs from bosses (Freya & Vezzax's Vein) will be taken into the bank and sold for a 75% price of the current AH price to guildies. (determined by a Officer or higher) Even patterns that drop from bosskills in hardmodes or in 25 ToC, will not be rolled for, but be sold to the highest bidder.
This money is in turn used for buy raw mats, food or pots which are free of charge.
4. Do it yourself.
Basically the bank will just be one big storage space for people to put and remove stuff from. You will have to get your own flasks, pots and food. Fishies and Flasks are no longer provided by the guild.
5. Your Idea
Don't like any of the idea's above or want to combine or have your own idea?
Feel free to tell me this in a comment!
I'm currently using this as a poll question for my guild who is not actively raiding in 10/25 man and thought why not share it with people