If you want relatively cheap and durable, go with the Micromachines they had in the 90's. On eBay I found a 3x X-wing set NIB for $13, and several lots of loose ships for even cheaper. There are also converters you can buy on Shapeways that will allow you to retrofit them for the X-wing Miniatures Game.

My older kids play and like it...I don't think they get/ or even care about the squad building. So I just pick the forces and run it like a scenario.

edit --- As far as age, I think every kid is different...but it is the content that determines their interest..some of my kids like starships, some like board games, some like swimming..so if you find a game that interests them it is all good. If they are being dragged into playing, forget it..age doesn't matter.

My boy started playing simple wargames when he was 5 and is fairly accomplished at most he is only 8 now. Regularly beats me at Star Trek: Attack Wing and plays against adults in X-wing tournaments.

I would second the notion of not letting them win all the time. While you need to let them win sometimes or they get discouraged, I think one of the most important things they can learn at this age is how to lose. I let my son bring his falcon with a HSF setup, and I bring enough Academy ties to come close in points. We do not use asteroids, so all he has to do is not fly of the map and roll the dice. He wins about 40% of the time. When he does, I get to break out "great kid, don't get cocky" even if he loses, he usually dust tie or two, and it's not that easy to win with 4 Academy tires against that. I suggest stacking the deck in their favir but then playing to win. No PtL with soontir or anything, keep it not too complex. That way you can work on your game by playing your best. And occasionally, let the wookie win.

My son used to know every ship, planet, and captain in SW when he was 2/3. I wish X-wing was around at the time, or at least that I had known about it. We got into 40K when he got a little older and he has been huge into it since then (15 now). He is one of the best painters at the local shop and definitely the most educated in the game with the most well planned army and tactics. We recently discovered X-Wing and are just starting to add it to the game table. My daughters (7 & 8) easily play and understand the rules, but their attention is not quite as strong, so it makes it a lot easier to skip the "actions" and stress tokens and basically simplify it to:

Pick equal point matched pilots, skip the modifiers.

1-set the dials

2-make the movements (in reverse skill order)

3-make the attacks (in skill order)

4-repeat until ships are destroyed

My son and I do this truncated version all the time to play quick matches late at night. This is great for teaching kids to think three steps ahead of what they are doing (game or life) and anticipate where things will be based on what you know (also great life lesson). I think most kids would pick this up rather quick even at 3 or 4, then later you can add the point system and the modifiers and the actions. I don't like "letting" any of them win, I think that learning defeat is just as important. I play it like an actual dogfight, sometimes Luke has 4 ties on his tail and he is simply outgunned... they generally come close to beating me, but rarely do. It is always a matter of "oh, now I see what you did, I will get you next time." This also make the times they do win even greater because they see my look of being defeated, lol.