Fluxx is a cheap and simple card game, the best draw being that it’s so light on rules – you draw a card and you play a card. Rules and goals change according to what’s on the table so nothing to learn up front. Several variants of it (pirates, zombies, space, etc) too.
Bohnanza is also a card game – lots of different types of bean, you’re trying to grow the largest bean plants but you can only have a couple on the go at once. Lots of trading and negotiating between players to get what they want. Light on rules but quite a bit of depth.
Carcassonne is a good shout, tile-laying is really easy to figure out. Skip the rules around farmers for the first couple of games though, just score the castles, roads, etc. Inns & Cathedrals expansion gets you the bits for a 6th player.
Love 7 wonders and it’s my usual go-to for that many people. Bit heavier on the rules, etc but still very easy to pick up.
And of course, learn the game and figure out your rules explanation before you sit down to play.