You can buy individual fonts to use on your covers, no need to buy special software. Just download them onto your computer and away you go. The only thing to watch out for is any licensing restrictions for their use, particularly if you download free fonts.
If you literally type the word "fonts" into Google, a load of sites come up, both paid and free. Most will show you what your title / author name will look like in a chosen font or range of fonts before you buy/download.
If you literally type the word "fonts" into Google, a load of sites come up, both paid and free. Most will show you what your title / author name will look like in a chosen font or range of fonts before you buy/download.