hey i dont remember which guy was playing the mage but if you charge anyone for portals/food/water you are a dick
You're making someone take time to do something for you. For food and water, unless if they are like RIGHT NEXT TO YOU they have to stop whatever they are doing, walk all the way over to you (wasting their time), cast a spell (more time), trade (even more time), and then walk all the way back. With portals, they have to buy a reagent ($$$), come to you (time), cast a spell (time), if you're doing a round trip that's another reagent and another portal (time & money), then they have to go back to where they were.
General mage etiquette is free food/water if asked nicely, tip for portals unless if the person provides their own rune. (and even then a small tip for wasting their time is nice)
It's a service, a tip is nice. It'd be the equivalent of not paying a waitress a tip, or a rogue a tip for lockpicking, or a lock for a rit of summoning, or a crafter for crafting, etc.
It costs like 20s for something that wastes their time to help you. Just fucking do it!! Not doing it is kind of dickish, and you can get back like 20s in 5s.