Buy Mode in the Sims 3 is like a built-in catalog that you can use to purchase furniture and other goods for your Sims. Using buy mode is necessary for improving the quality of your Sims' lives with better furniture and appliances and so on. Read below for details about the types of items that you can purchase for your Sims.
Kitchen
Kitchen goods are necessary for satisfying your Sims' motives. A Sim can get by with just a refrigerator to start out with.
Refrigerators
Refrigerators can store ingredients, fish, and cooked food. In addition, if a Sim attempts to make a meal for which he or she doesn't have the required ingredients, the needed ingredients will be purchased automatically through the refrigerator. Food in refrigerators goes bad eventually, although higher-quality refrigerators keep food from spoiling for a longer time. In addition, food stored in higher-quality refrigerators will satisfy hunger more effectively.
Stoves
Stoves have an oven and a range. Your Sim will automatically use the appropriate one for a given meal. Higher-quality stoves make it less likely that you'll burn food. There's even a stove that speeds up learning of the cooking skill. Stoves can be upgraded to be fireproof or self-cleaning.
Microwaves, Food Processors, Coffee Makers
These items are not strictly necessary for gameplay, but they can add a little convenience to your Sim's life. Microwaves can help less skilled Sims learn the cooking skill more safely.
Counters
Counters are important for meal preparation. When cooking, your Sim will need a surface to prepare the meal on. If no counter space is available, your Sim will walk to the nearest available table or other surface. This can waste a lot of time, so be sure to outfit your Sim's kitchen with adequate counter space. Some sinks are specifically designed to be installed in a counter.
Dishwashers and Trash Compactors
Not strictly necessary, but they can add convenience. Dishwashers make it so your Sim doesn't have to take the time to wash the dishes by hand. Neat Sims can get their moodlets improved by using the dishwasher. Trash Compactors make it so your Sims don't have to take out the trash so often.
Sinks
These can be used just like bathroom sinks, for washing hands, washing dishes, and so on.
Living Room
The living room is where Sims can gather and do activities together.
Televisions
From Televisions, Sims can learn skills from the higher-end models. They can also exercise. Or, of course, they can just zone out and be a couch potato. Video game systems placed next to a TV can make it so your Sim can play games on the TV.
Video Games
Put a video game system next to your TV and your Sims can play games.
Stereos
Sims can use stereos to exercise or to dance with other Sims.
Bedroom
The bedroom is where your Sims sleep.
Bed
The quality of the bed determines the quality of sleep that your Sim will get from it. Some of the cheaper beds are so poor that you will be struggling to keep your Sim happy and functional at all. The more expensive beds allow your Sims to refill their energy with a smaller amount of sleep. A good bed is one of the most important things to invest in. The Single Sophisticate bed is the best, although for couples, a Sleep Slave Bed is also a good deal.
Alarm Clocks
Alarm clocks can be set to wake your Sims up for work. It will automatically go off an hour before your Sim has to go to work. This doesn't give you much time, really, so you might want to get it just as a backup in case you forget to manually wake up your Sim.
Bathroom
The bathroom is where your Sim takes care of the Bladder motive.
Toilet
Cheap toilets break more often, but a Handy Sim will eventually make all plumbing objects unbreakable after achieving the plumbing handiness challenge. Or you could go for the expensive toilet that never breaks.
Showers and Baths
Cheap showers break often and are slower to increse the Hygiene motive. The most expensive showers never break, are self-cleaning, and boost your Sim's hygiene very quickly. Placing bubble bath on the tub allows your Sim to click it and choose to take a bubble bath. This is useful for Sims with stressful jobs.
Sinks
Sinks are useful to have in the bathroom so your Sim can wash up after using the toilet, since after using the toilet your Sim's hygiene will decrease a little more quickly.