i like games like this, good game id say, maybe give a setting to auto remove bodies, because im gonna go have dinner and im sure it will be lagging like hell when i get back, but im sure that's hard to help.
Ok, as the walkthrough link doesn't actually work, here it is:
From the start *PAUSE* then buy about 20-30 cereal and then blow the rest of the money on meat and fish, buying at least in batches of 20 with 30+ being ideal. Stock this all right away to avoid any wastage. Having done that resume gameplay, in double speed and watch as the customers buy all your expensive goods (set all prices to RRP). Now as the game progresses you want to be buying all your bulk (30+ increments) on the day right before you have to pay bills. Pause before you buy just before the bill day(don't worry about having negative money for a couple days) anyway, buy expensive products such as meat, fish, candy, pizza, eggs etc. this will give maximum profits. Do this until satisfied and after a while get the store advertising and TV advertising in marketing. Also upgrade some shelves if you think it is suitable.
On positioning goods, try to avoid having any of the same items in the same aisle, so spread around the fish and meat along the store, but remember the aisle nearest the door with "Special Offers" nest to it is the fastest selling aisle, so use that wisely.
Good luck being a millionaire!
I find buying the high value goods like meat and fish from the start works pretty well, plus cereal always seems to be the trend from the start so don't bother with research right away.