Hang on, do some research first. If the software is new it will cost much more. Support for older cheaper versions of software will not usually not be included.. Case in point, I did a search for a keyword program and clicked on the ad for Brainstorm Generator, software to find keywords for profitable niches. The program looked interesting enough for me to do a little investigation. It was advertised as a $10 download.
Many internet marketers have ads for cheap software including ebooks on eBay. I did not find any ads for cheap software listed on eBay, which was my first search. Then I searched the web and guess what, I found a site selling the same software for $2.95.

Total research time, 5 minutes. In another minute I determined that the software was over three years old and then had sold for nearly $300. Old versions of software may still have some value.
What that really means to me is that someplace I can probably find it for free. A $7 saving for 5 minutes isn't bad.

Finally, if you have the time and inclination to search more thoroughly, software can often be found for free.