It used to be difficult to find a reputable orchid supplier not so long ago, but with popularity of orchids today there are now lots of options available to find a good plant.
Orchid specialists are your best bet for a healthy plant and good orchid information. Most of them started out just like you as hobbyist, and they became growers and suppliers as their love for the hobby turned into a business. They will know all about the plants they sell and will be willing to help you pick a plant that is best suited for your abilities and growing environment.
Local garden centers that grow orchids for sale would be the next choice. For starts they are convenient and they are more likely to grow plants that can be grown successfully in your area. There will normally be someone there to provide the proper orchid information for the plants they grow and sell, and they should be able to help you with the supplies you need to properly care for your orchid.
Growers at orchid shows will often offer plants for sell. However a majority of the plants there may need more expertise to grow than a beginner has. It would be to your advantage to know what kind of plant you are looking to buy before you attend. Sometimes the beauty of the orchids on show gets the best of buyers and they buy orchids they cannot provide the right environment for.
Online orchid suppliers offer a good selection of orchids and many of their sites have large amounts of orchid information available to help you choose your orchid. I suggest you spend some time on an orchid forum and ask others there for reputable sites. Other members are always willing to help. Forums are a good place to stay in touch and the members can help you with your care question.
Home centers and discount stores have recently begun to offer orchids because of the popularity orchids have now. Usually the only orchids they carry are the ones that are easiest to grow. This is a good thing. However there will be nobody there that will have any orchid information to offer you. If you decide to buy from a home center or discount store because of the lower cost and convenience, try to find out what day their flower shipments arrive and purchase a fresh one that day.
If you purchase your orchid locally there are a few things to consider when taking your plant home. If the plant was kept indoors where you bought it you will want to try to match the temperature in your vehicle to the indoor temperature. This also goes for a plant that was kept outside. Do not put it in your car and turn the air conditioning down to 70 or you will put your plant into shock. You must also consider the light. Try to keep the plant out of direct light especially where it can be magnified through a window in your car and burn the foliage of the plant. I would also take it straight home just like you would if it were ice cream. In addition, I would not water or re-pot the plant in the first 48 hours after bringing it home. Let it get used to the environment it will be living in.