For the automation of the auctions the player could inform the lower and higher price for each good to be auctioned and a ranked list of goods needed.
The bidding price is a bet on the duration of the trade. Because the trade will be valid until the trading partners decide to put again the good on the next auction. Thus, minimum duration is 3-6 months (depending on how many sales are done in one year), and maximum duration is the whole game if the trading partners remain the same and wish to keep it that way (probably the most profitable option but may be not on the interest of both parties).
For example:
2u Grain Min: 0.2 (selling price only) Max: 0.5 (buying price only) Province *
1u Stone: Min: 0.1 (selling price only) Max: 0.6 (buying price only) Province *
etc...
* This could be for each province or on the national level as previously requested on this forum (
@WhyWhimsy Meaningful Trade POP driven demand)
The program will automate the auctions for the player, asking bids for the goods that match the ranked list. For example:
Bidder 1: asks 0.3 for 1 grain put on sale
Bidder 2: asks 0.4 for the grain
Bidder 3: asks 0.5 for the grain
Bidder 1: stops asking because his maximum bid price is reached
Bidder 2: asks 0.6 for the grain
Bidder 3: asks 0.7 for the grain
Bidder 2: stops asking because his maximum bid price is reached
Bidder 3: gets the trade and has to pay a fee of 0.7 x 10 gold
Thus, the bidder 3 has won a trade that will produce 0.7 gold/month for at least 6 months (we consider two auctions/year), total = 0.7*6= 4.3 gold but it has payed 7 gold for this trade. If the players can keep the trade for more than 10 months (2 auctions) then the trade is profitable. The fee is to stop the bidders increasing the Max price artificially to maximize benefit in the short run.
Why would a nation stop a trade that is more profitable on the long run? For many reasons:
- They do not produce the surplus anymore (Civil war, slaves revolution, famine, diseases, etc...)
- They do not want to benefit the trading partner anymore
- They think they can get a better bargain in the next auction
- etc..
EDIT: rich nations will get their ranked trades first if they put a higher bidding price but they will be limited by their trade routes. The fee will act as a gold sink for the high bidders.
Trade will be available for other nations if there are more goods put on sale than overall free trade routes.
The scarcity of goods to sale that exists on the game is not solved by the auctions. The auctions give the player an option to get the trade by spending money upfront. It also creats a new subgame with other nations, increasing the rivalry feeling when competing for the same goods or the cooperation when trading for long time with the same partner.
EDIT 2: the trade window could have two tabs, one for the auction ranked goods and bidding prices and another for existing trades with trading partner, start date, starting fee and accumulated wealth since start date.
EDIT 3: modified the concept of min price for selling and max price for buying to avoid sploits.
If a player decides to buy with a min price too high it can game the system, outbidding all other players and getting a very high price (100g/month) that if he has the money to buy (1.000gold) and the trade is not interrupted, can be too much. For that reason, players will not be able to set a minimum price when bidding and the auction will start with 0.05 with steps of 0.05 until there are no other bidders left.
On the other hand, when selling a product, the player could decide a minimum price and not sell below that price, to avoid selling the product if that price is not reached. The auction will start from 0.05 until there are no bidders left, if the price set by the player is not reached, the auction is void.