Pure Mac has a large selection of software to choose from, sorted in categories that are easy to use. And ZDNet is another site that also boasts a large, sorted archive of Mac software. These are known as Shareware. Shareware is software that is crippled. This means that it won't always have all the features of the program, unless you pay for it.
Some programs are cheaper than others.
The free software, known as Freeware, is just that- free. Yet, be on the lookout for another type of free software called Warez. Warez is illegally hacked programs that have been picked apart to access the full program, without paying for it. Needless to say, this is against the law. But it's not against the law to begin your Internet search for that software programmed to unleash the fun waiting to be had in that family computer and discovering what the big deal really is.