Trade mechanic...

Well, I wouldn't call it a trading mechanic, as you are not actually trading something, are you? Not with other players, nor with the "game". It's more like a buying mechanic.

Semantics aside, if really the only problem was the amount of shuffling then there are several ways of combating that. You could raise the number of cards in the deck. You could lower the number of different goods and offer less cards per turn (for example, 4 instead of 5). Another option is not to discard the unused cards, but let them stay there face-up for a next turn, and only add as much cards as were bought (refill up to 5). This will slow down the turn-around time of the deck, and perhaps also add some interesting decisions.

On the subject of Rain Man... Have you played the Coldsnap cards in MTG? I've been doing a few pre-release drafts, and there are a few cards with a 'ripple' mechanic.

Essentially, it works like this: You play the card with ripple on it, and then you may reveal the top four cards of your deck. Any cards with the same name of your first ripple card can be played for free, and the remainder go on the bottom of your deck. Of course, you can then ripple the one you played for free... I've had great fun with grabbing 5 or 6 copies of a single card in the draft (draft doesn't have the four copy limit), and being able to ripple all of them out to devestating effect... but I digress.

The point is, some players CAN remember card order of cards put on the bottom of the deck. I make a point to remember what cards go back and in what order. You can probably avoid this by having more than 40 cards to deal with, though. I imagine if the goods deck had 100 cards in it, I'd have a bit of trouble remembering the exact order, especially if the variety is only 7 types of goods.

Just calculate the buying and selling one item at a time.

Price List for Buying or Selling
-----------------------------------
1 available: 5 gold
2 available: 4 gold
3 available: 3 gold
4 available: 2 gold
5 or more available: 1 gold

So if there are three, um, nice wooden staves available, and you buy them all, you pay 3+4+5=12. If there are three staves available and you sell 5, you earn 3+2+1+1+1=8.

As long as you're dealing with small amounts of items, I don't think it's that fiddly. I've always wanted to include this system in a game. :)

i am thinking about this aswell.
Example:

The players have different resources lets say x,z, y, t and these resourses can be traded but when u sell them i am planning to add money as a way of payment, meaning u dont get z for trading t but insted u get money.

My intention is to let the players use money to buy the different resources from the "bank" and from the other players.

BUT, i dont know how i should handel price changes in the resources and i am affraid that it gets fiddly escpacially if u have to track all the resources produced and used.

One could of cource let the prices be the same during the entire game.

//Johan

I think for trading and selling comodity, "Puerto Rico" and "Settlers of Catan" are 2 great games for inspiration.

In the "Uncharted Waters" video game, when you always make the same trade route and sell the same comodity, the price drop since there is a lower demand. You could represent it like this :

You have 3 slot with a value of 4|3|2. When the first player sell a commodity of this kind, he gains 4 gold and place a token on it leaving 3 and 2 free. When all 3 slot are occupied, there is no more demand for this commodity and nobody can sell it anymore. You just determine what event can occur to remove tokens in these slot so that players can sell again.

Trading between players is also a good solution because it naturally creates a offer and demand mechanism. If you produce too much of a type of good, you will eventually want to get rid of it. You just need to determine how much good each turn will enter and exit from circulation between players. This make sure that there is always a certains amount of goods in play.

It's an infinite Peanut/Gold loop!

I think you would need two prices for buying and selling, shifted slightly (to maintain the even buying/selling price):

Sell:
0 available: 6 gold
1 available: 5 gold
2 available: 4 gold
3 available: 3 gold
4 available: 2 gold
5+ available: 1 gold

Buy
1 available: 6 gold
2 available: 5 gold
3 available: 4 gold
4 available: 3 gold
5 available: 2 gold
6+ available: 1 gold

So, if there were 4 available, you would buy at 3 and sell at 2.
If you bought two and sold two, you would buy at 3+2, and sell for 2+3.

If there were 7 available (for example), and you bought three (1+1+2), you would sell them back at (2+1+1), so it also works at higher values.

Problem solved.

Fair warning: I'm going to use (steal) this trade mechanic and use it in my Pirate game. On the upside, I will probably never publish it, so don't think I'm going to beat you to the punch. However, I will tell you how I am going to implement it, so maybe this will help you out.

In my game, there are 12 ports (Booty Bay, Cutlass Cove, Port Plunder, etc.), each distributed around the edge of the game board. I think I'm going to reduce the number of types of goods from 12 to 6. Probably going to use Rum, Guns, Silk, Dyes, Lumber, and Sugar.

Sell:
0 available: 5 gold
1 available: 4 gold
2 available: 3 gold
3 available: 2 gold
4+ available: 1 gold

Buy
1 available: 5 gold
2 available: 4 gold
3 available: 3 gold
4 available: 2 gold
5+ available: 1 gold

Now, here's where it gets interesting:

To encourage sailing across the seas, 6 of the 12 ports will have a high price for a particular trade good. For example, Booty Bay might have silk as a high trade good. Prices (for both buying and selling) will be 1 gold higher than everywhere else. The other 6 will have a low price for a particular trade good, where prices will be one lower than everywhere else. Yes, this means you can potentially 'buy' for free at a low port if there are enough available. So, if Port Plunder has the low price on silk, you could buy it cheap and sell it high at Booty Bay.

The only problem I see people posting about, is that all of a particular good will be shipped from the cheap ports to the expensive ports. This shouldn't be a problem, however, because if all of the silk ends up at Booty Bay, you will be able to buy it for 2 gold, and sell it at Cutlas Cove (or any of the other 10 ports) for 5.

If anyone is interested in the other aspects of the game, pipe up, and I'll start a new thread about it.

Jebbou brings up the interesting point of the middleman. Perhaps the market stays the same for all ports, but the traders and buyers have different markup rates? So if the markup on parrots in Barnicle Bay is 2, and the current value of parrots is 2, you can buy a parrot for 4, or sell one for 2. If the markup for peg legs was 5, however, you might want to sail to Gangplank Market, where the peg leg dealer only charges a markup of 3.

This way, the market fluctuates based on goods available (the same for all ports) and the dealers of the commodities (different for every port and commodity).