It's a pity that in PixelPlaza you can't buy things from other houses made by other people... not actually BUY for no reason, but buying, for example, the furniture to increase the value of the house, that's just an example of my idea. 
Some users told me to do the big list below:
Food:
Basmati rice: 6 PPC
Basmati Pasta: 7 PPC
Vegies (every single one there is): 2 PPC each
Cod fish (eew!): 3 PPC per pound
Normal fish (still eew!): 3 PPC per pound
Frozen meat: 5 PPC per pound
Packet of chips: 2 PPC
Burger pans: 1 PPC
Kitchen stuff:
Whole kit of places setting: 50 PPC
Normal Frying pan: 20 PPC
Hyper frying pan with radio: 45 PPC
Normal Dishwasher 100: PPC
Mega Dishwasher 5000: 650 PPC
Normal Washing-machine: 100 PPC
Super washing-machine: 600 PPC
Oven: 375 PPC
Refrigerator: 700 PPC
Furniture:
Dinner Table: 550 PPC
Breakfast table: 425 PPC
Chair set: 600 PPC
Bookcase: 625 PPC
Flat screened plasma TV: 750 PPC
Couch: 500 PPC
Single Bed: 600 PPC
Double Bed: 875 PPC
ATI mobility radeon X1600 graphics computer: 900 PPC
Desk: 725 PPC
Wardrobe: 775 PPC
Toys:
Teddy Bear: 5 PPC
Collection car: 20 PPC
Doll: 7 PPC
War toys set: 14 PPC
The idea of each product is mine, but the general idea is Chiya's and maybe more users'.
04/07/2006
The creation of the supermarket.
04/15/2006
I added a shadow to every letter and added a better pattern to the grass.
07/21/2006
Added the door cabin on the roof, the little window and the vent.
Made with: MS Paint and to transform into a gif file i used Giffy 2.0.