Most software development companies would offer trial programs for a limited time. These are commonly known as shareware or freeware. However, in these downloads, not all options are active. These are usually enabled once a person is interested in them or would pay to use them.
There are also cases where downloaded programs are not the software itself. A person would be either sent via shipment the actual software or given a link to which they can download the full working copy.
The cost of owning full software rights would depend on the intent and means for utilization of the program. Sophisticated programs would usually cost more than small ones since their level of programming and benefits are far more in demand. Complications with regards to the level of programming will always have a say on the commanded price to own such.