Kids in the past used to play together. They'd either play at one friend's house or play together in a neutral location. They brought along some toys and had quite some fun playing with toys that weren't theirs. This, however changed as people became more protective. Your next door neighbor could be a psycho but if you have but if they have kids of their own, it could be that they aren't as bad you think they are. So if you have a good neighbor and your kids get along would it be a good idea to buy toys together since all your kids will be playing with them? You could even get bulk discounts if you decide to buy lots of toys at one go.
I honestly don't know that in good conscious I could do this -- while the idea seems stable, if I don't know the other parents on a close personal basis I would not feel comfortable spending money on items that their kids may break. I mean I can punish my children and overlook the use of their items making sure they are treating their belongings responsibly. I have the right to punish my kids if they are doing something wrong. I cant say that for the other children. I mean if they just break something... the other parent may not have the same values I do. They also may not feel the need to replace it -- in which case the money was wasted.
I think it's an overall good idea, but I would only recommend it if your neighbors and yourself are on good terms. Something may gets broken (they are kids after all) , but since there are several children having the toy, it can teach them the value of sharing. If you don't have a lot of contact worth your neighbor, don't do this, cause there could come a lot of arguments like whose child gets to take the toy home, who's allowed to play first with it....
You could try filming a documentary on this and see the results! I think it's hard enough for siblings to share let alone neighbors. I know my friend who has three children, the two boys fight over their own toys and it's about who owns what, so it depends on the personalities. Maybe in poorer families it may work, but children like to have something that is theirs. I remember as a child I prized my dolls and would play with them with others, but I wouldn't have been happy sharing them.
If the toy can just stay on the ground like seesaw or monkeybars to which you guys will put on the shared ground, it wil be worth since these will help the social skills of your kids.
I think this sounds like a recipe for disaster, unless you are on extremely good terms with the parents. Plus, if you move away, then who would get to keep the toy? It might be a better option to each buy a playset, with the understanding that the kids could each play on each other's playset. That way, they learn how to share their toys, have double access to fun equipment, but there isn't the gray area of shared ownership or responsibility for something breaking.
I'd maybe up for doing that for the bulk discounts but unfortunately I don't know of any toy stores around here that would offer it so I mostly just stick to buying it myself. Also most of the toys the kids have are gifts anyway and we only account for a small portion of that collection so technically we don't even really buy that much to make it necessary to make deals with the neighbors.
Not a fan of it, it just makes it awkward to share when the kids are *not* playing together. It's fun when they do play together -- and for this, I'd guess that to build a common playground or swing or tree house would be great, really. But toys? Kids get attached to them, they want to bring them to sleep or on vacations, they have to move away, etc. I think that just makes it awkward to try to split it up. On the other side, I like the idea of renting toys from the library.
Less so for toys, but I think sharing the cost of a small playground/sandpit might work out okay. However a contractual agreement between parents over the use of it, and whose property it lies on would probably be necessary to avoid any conflict.