Tank for my betta

Question
I have had a betta for about 6 months now in a small quart bowl.  I hate to see him in such a little bowl and want to get something bigger, perhaps a small aquarium.  Also I am sure it should probably be heated too because now that it is getting colder out, I usually keep the house temperature around 60 degrees when I am out for the day and at night.  I went looking at some pet stores and just really dont know what to get.  I saw some 1 or 2 gallon complete sets and they just look kind of cheap looking.  There were some nicer looking 3-5 gallon ones in both a hex shape and a corner shape that looked decent, and I was thinking if I got one that size, I may want to put a couple more fish in it.  Can you recommend a good setup for me?  I have never had any kind of aquarium so is it best to get a complete set, or buy everything separately?  Also, I noticed the small complete sets do not come with a heater so what kind of heater would I need?  Is that a good idea to get something around 5 gallons and put a couple of other fish in there with him, and if so what kind?  Is a live plant a good idea in there, gravel or rocks, etc.?  If you can show me something from the Petsmart or Petco websites that would be great because those two stores are the ones close by me.  Thank you!

Answer
Your Betta will love the new space. Betta's are hard to add to social aquariums. These are aquariums with more than one type of fish. Betta's are very aggressive towards fish they might see as a threat to their beauty, especially fish with long fins. However, some sucessful tank mates have been Tetras, Rasboras, Angelfish, Placos, Corydoras, or African Dwarf Frogs. Snails and shrimp will get eaten, however Betta's  do enjoy munching on an occasional Ghost Shrimp.

The Setup:
If a social tank is something you want to try, then a 5 gallon or larger tank is a must. Those 3-5 gallon hex tanks are great, I love he way they look when they are are set up. Buy caves and rocks with hiding places so if the other fish feel threatened hey can hide. Live plants look great and provide healthy bacteria for the tank but they can be hard to take care of. Some live plants thrive on their own and others need fertilizer. Easy to take care of plants include Java Ferns, Vallisneria spiralis, and Hygrophila polysperma. I know you can purchase live plants at both Petso and Petsmart and they are usually pretty decent of a price. The selection will vary depending on the store. Usually your best bet wold be any type of plant with large leaves, as I found anything with tiny leaves has a tendency to make a real mess in the bottom of the tank. Plastic plants are nice too, especially the silk ones.

A heater is a very good idea, and you can usually buy one that is meant for a certain size aquarium. About 75 to 80 degrees Fahrenheit is a nice temperature for an aquarium.
Its very important to slowly add your fish in after the Betta is all setup. This way he wont be overwhelmed by everything.

Rocks are really nice, especially shale. Try to avoid limestone or sandstone as they can sometimes contain material that can pollute the water.

If you do decide to keep just the Betta, then any 1-3 gallon tanks are decent sized. My current Betta is housed in a 1 gallon hex tank.

Setting up an aquarium is a very rewarding hobby!