Once you are happy that you understand what software you need then you can go shopping. The easiest place to buy software may be from one of your local retailers or shops that sell computers. At these stores you can often ask questions about the products and maybe get to see a demonstration if you wish. If the software should be faulty then returning it to the shop should be straightforward.
Buying online is probably the most popular place to get software as there are often some fairly aggressive discounts to be had. As always let the buyer beware and source your products from a reseller with a good web presence and reputation.
You may be tempted to buy software from an auction web site. The choice is yours but be very careful that you are buying genuine product and that it has a proper software licence or you could be buying illegal software. You may wish to read more about buying online in this guide here.
Here are some software resellers that may be of interest:
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