Family space themed adventure: Trading commodities

This is a little bit of "mechanic" and a little bit of "idea", so not sure of the best forum to post on, but here goes...

I've got a space themed adventure game in progress that should be suitable for family play, accommodating a fairly wide range of ages. This is partly due to asymmetric roles picked by the player. Some roles are more straight forward, some will require more complex thinking, and have different ways to achieve victory points. (Think: trader, pirate, humanitarian, etc.) (er... humanitarian... hmmm, what would the correct be here as there are aliens? Xenotarian?)

Anyway, one element of the game is to make money by trading resources between planets. Now, I want this to be interesting for players who like trade, but it also has to be approachable for younger players.

Instead of every planet having it's own prices (complex), I've classified the planets into 3 broad categories, say red, yellow, blue which trade in 4 commodities. Each color planet shares the same prices with the same color. (simpler)

Each planet deals in all 4 commodities, but for OPTIMAL trades, I've gone with a rock-paper-scissors configuration. So you can buy red items on red planets for cheap and sell them high on yellow planets (or medium on blue). You can buy yellow items on yellow planets and sell them high on blue, and buy blue on blue and sell to red.

So for a younger player all they need to know is buy the red stuff at red planets, etc. While an older player may look for increased efficiency in the route taken, and watching for opportunities in price fluctuation. (info about price flux at the end)

So, first question:
Thematically, I haven't decided what makes the most sense for what the planet classes and the commodities actually are.

Right now I'm thinking:
1) Food ($) / Ore ($$) / Manufactured Goods ($$$)

Red (Frontier/Mining) buys Food high, sells Ore low
Yellow (Production) buys Ore high, sells Manufactured Goods low
Blue (Developed) buys Manufactured Goods high, sells Food low

Or:
2) Food ($) / Industrial ($$) / Luxury ($$$)

Red (Frontier) buys Industrial Goods high, sells Luxury Goods low
Yellow (Production) buys Food high, sells Industrial Goods low
Blue (Developed) buys Luxury Goods high, sells Food low

What would fit well for a wide range of planets and goods that fits in a rock-paper-scissors model?

------

Ok, next part:
You might have noticed that I originally said 4 commodities but only list 3.
The 4th I envision as contraband items. These are an optional item you can buy cheap and sell for a big profit, but at a risk of getting caught with them.

(This can remain themed as Contraband, as this is a family game, though it could conceptually represent anything from weapons, to drugs, to muffins made by people your faction doesn't like.)

I have two solutions so far:

1) Buy Contraband low at the frontier worlds and sell high at Yellow and higher on Blue. Faction has no bearing.

2) There are 2 Contraband items, one for each major faction. You buy them low at the faction that owns them and sell high at the opposite faction.

Option 2 adds a 5th commodity and I dislike it for this reason, but perhaps adds more difficulty in obtaining them - in addition to getting caught with them. However option 1, while simpler, tends to disrupt the rock-paper-scissors rotation a bit. Right now I'm leaning towards option 1.

But perhaps there's another way to go about this. Any thoughts?

------
Oh yeah, price flux. So, I'm thinking that periodically a custom die can be rolled that changes the overall price of a commodity. A single item is temporarily raised, or lowered, across the board on all planets. The new prices are listed on a color coded die face. You'll still want to buy red stuff at red planets, but a savy trader could find ways to work the market.