I wish you well, and I am not here to rain on your parade, but to inject caution and reality:
Regardless of friendship, you will have to pay for hay and feed. Friends are not providers of free stuff for very long, and that is a quick way to lose friends. These things must be grown, cut, processed, packaged, and delivered. All of which costs.
1.5-1.8 acres is not much. This area will cost money and time to maintain, and you will likely be supplementing all year round.
You will not be able to chose the cheapest vet, you will have to chose the nearest good equine vet. Allow $500 per annum per horse for routine vet bills, and save $4000 in a pot somewhere for emergency vet costs. They happen....
Wormers you have to pay for, vaccinations you have to buy even if you are administering yourself.
My 'shoeless' horse has just finished 9 months of front shoes because of a relatively minor hoof crack that became major, that eventually had to be drilled out by the vet. Sometimes shoes happen...
The owner of the boarding horse is responsible for all their horses costs. Do a search on boarding agreements for more info on them.
Finally - I know this is a lot to learn, and kudos to you for seeking out the information. Fools rush in where angels fear to tread, so I congratulate you on not being a fool.
We would get hay and grain from friends, farrier here charges $35 dollars for trim, would have ~1.5-1.8 acres, we have apples growing there, so practically free treats, and my parents would most likely just pick up a pack. Vet... Umm.. My cousins fiancé is a horse vet, I'm not sure if she actually lives in this province though, so I could probably just ask her to point us to another vet that is good priced.
I think we can handle the worming and things, and I forgot to mention, we most likely won't be getting her shod, unless its insisted.
Is it fair, if there's a person keeping their horse with you for $100 a month, you just give them food, check them for injuries, pick their feet, let them stay in the pasture with shelter and water, and supplements, like the basic needs? Or would we also pay farrier costs and vet stuff and other things, or do they pay it?
And vets usually float their teeth, correct?
(Ooh, my grandpas learning
he now knows to not use barbed wire )