@TBC
IF you want to start somewhere, go with LnoE. Its a really good game and up until Zombicide, our fav coop Zom game. Scenario driven, dice rolls for movement and cards for items and altering actions.
Movement is simple (zoms 1, humans 1d6). Cards can help Zoms move farther
Items acquired by searching rooms and can be traded between ppl.
I think you can have 6 or 8 humans and the zoms can have 1-2 players, but I usually play the zoms alone vs the rest of the table.
you can probably find it cheap on ebay or trade it for something.
Z-cide is a definite move up in the right direction (I considerate the next step up from LnoE) but the price is a def. drawback.