Hah, I played this game 3 days in a row and beat the main story (about 9:40 playtime) XD
I was saddened to hear that the main story would end at 500K price (36th day), since I had just hit the 200K payment already.
Was a little surprised to find (from various sources on different forums) that people had problems hitting the last two deadlines. I beat the 200K (with only about 105K about 5 days before deadline) one with over 250K left over, and beat the 500K (with only about 150K 5 days before) one with 560K left over. Basically, in both cases I basically quintupled (or even more) my liquid cash in 5 days XD BTW Most of the extra cash (as in, the cash over the required amount due) was made the day before and the day of the payment date. The days before were devoted to buying enough stock (often putting me even lower than what I started with), and selling enough to reach the required balance on the due date.
Thank goodness for Food and Armor price hikes XD The food ones tend to last two or more days at a time, which means that so long as you stock up on food at some point, you'll make a mint if you fill your store with nothing but food (the highest price ones on display). Food is also an item commonly sold to you by customers, and they don't really expect much for them.
BTW: If you've hit a food price hike with only a bit of food in stock, don't be too afraid of buying the marked up food in the market, you'll still make a mint unless the shortage runs out all of a sudden.
At least, that's my experience with food price hikes, maybe the game is a bit more random with other people *shrugs* Oddly, weapons seemed to suffer regular price drops (one time swords were low priced for like a week and they still haven't properly recovered for me, what happened to the rumored price hike on longswords? That never happened for me, so long have I had 5 of those swords that never seem to normalize in price >_<).
