There are many different places to get your plants. Often the most easily accesible are mega chain nuseries like you might find at Wal-Mart, but there are a bevy of local growers whose entire businesses are dedicated solely to the art of raising plants. These local growers will inevitably have superior product, be more knowledgable about their trade and are generally more friendly. Supporting your local businesses is good for your local economy, your community, and you. A budding budget guerilla gardener might do well to scout out public spaces where easily accessible plants can be tastefully uprooted and transplanted, or borrowed from to begin building their own garden.
Be weary of supermarkets and drugstores. Many of the plants they wish to sell you are quick flowering ephemera. These angiosperms (flowering plants) will only last you a springtime; summertime if you're lucky. These types include pansies and other "ColorSpot" plants. For a more long lasting joy, look for the green foliage such as ferns, tropical plants like those ivy that can grow long tentacles you can drape on your window sills.
This plant is commonly seen plainly labeled as tropical plant in grocery stores, hardware stores, and can be found in many college dwelling apartments. They can also be seen in dentist waiting rooms, small torta restaurants, and on the desks of many underpaid receptionists. Do not fear these mundane plants. They are fast growing, hard to kill, and can be propagated in the blink of an eye. Sure they don't produce bi-sexual conspicularities (flowers with showy petals)- but do not judge, for they are faithful and loyal housepets to the busiest, the laziest, and the most irresponsible of human beings.
This plant is also commonly labeled without care. It is Hedera (Ivy) and is commonly known as English Ivy. This specific specimen is a form of Hedera Helix which just means the leaves are smaller and are for "decorative purposes". This one is a slow grower and can be left alone in the dark, unwatered for a month. Although a little more attention needing then the above, it will suit the novice plant keeper just fine.
Aeonium can be found anywhere. Look to universities, specifically in the back of humanity libraries. All you have to do is cut a stem attached to a fine looking rosette. Take her home and place her in a vase of water. Once the roots emerge, plant her in a pot with well drain-able soil. If all you have is standard potting mix, try to mix 1 part sand with 3 parts potting soil. Be sure to put a blockage over the drain hole. A rock or a piece of scrap wood works well. Fat toy soldiers work better.
This succulent also comes in a nice dark purple shade. Look around and see what you can find. Look for its fleshy leaves and thick stem. Once this succulent is well established, Aeonium will branch off with new rosettes and will either self propagate or just grow new branches.
If you must buy from a supermarket chain try to buy from Trader Joes. There are many little decorative potted succulents displayed right outside the entrance. Just remember to check if these desert friends have good draining pots. If they don't, you can always re-pot them later.
Haworthia Fasciata is also known as Zebra Plant or Zebra Aloe. I got my plant at Trader Joes and re-potted it in a nice clay pot that drains well. When in full sun, this plant will be happy.
Edit: It has been brought to my attention that "conspicularities" is not a word. The person who pointed it out to me commented that it sounds like "peculiarities". Let me justify my word choice:
He is correct. It is a joining of two words- conspicuous and peculiarities. The fact that some plants flower (angiosperms) is quite a feat. Flowers are present after millions of years of painstaking evolution. The mere fact that plants have evolved reproductive organs (some female, some male, some both) is quite amazing, and justifies a birth of a new word.