The facts this guide has been made from involve the first 10 day, checking with other files for comparison, and lots of day restarts. It's possible there are some sweeping changes after day 10(factory production changes, recent 'issues'), but this is a good start. If I find out some such later on, I'll update this.

It's rather simple. As one might have guessed, there has already been discussions about some merchants that will reliably sell/buy at higher/lower rates. But, I've put together a full list. Things rise and fall, but these will stay enough the same.

Best prices:

Drinks: Florence and Everett
Canned food: Clinton
Attire: Florence and Everett
Personal Health: Gail
Fresh food: Clinton and Lloyd
Liquors: Gail and Everett
Luxury: Florence
Combustible: Clinton and Lloyd
Medicine: Gail
Toys: Lloyd

Highest prices:

Drinks: Lloyd
Canned food: Gail
Attire: Lloyd
Personal Health: Florence
Fresh Food: Gail
Liquors: Clinton
Luxury: Everett
Combustibles: Everett
Medicine: Florence
Toys: Clinton

Now that you have enough coins to get an exclusive "Yellow ticket" to the grand event, you can also think about the many other things money can buy. And, even then, make sure you have either at least 100 coins or some items to sell back on hand. And remember, you can only buy 10 items per day. But, you also don't need to sell it all in one day. If you ever feel lost, check your warehouse inventory.

And, as a quick bonus, here are just a few things you can spend money on....

King in Yellow ticket 250
Park projects 300
Statue of Henry 200
Decorations 150
Church improvements 200

Rubbish cleaning 125
Rat catching 75
Union posters 175
Statue garden 275

Library access 400

Body procurement 200-400(Wink wink, nudge nudge, say no more.)

Also, all city projects(library included) can be payed in installments. You don't need to pay it all at once.

Coins can also be used with some quests you are given by characters. And, if lucky, I might be able to put together a quest guide. But for now, I think this should be enough for someone to get started and make some 'crazy' profits.