There are many ways to buy music for use in your projects.
A great number of sites exist with some really decent library music.
I have music for sale on a number of these sites and appreciate the hard work in marketing and licensing deals they make.

Buying directly from the artist or composer is another method in addition to the library or stock music sites.
Having creative freedom and the ability to upload and sell directly to other people in the creative industries is an important stream of revenue to songwriters, composers and musicians.

It also brings the benefit of being to talk directly to the composer themselves.

Hope you find some music that you think is great.