Once a fan makes a purchase, they get unlimited streaming via the free Bandcamp app for Android, iOS, and Sonos, an optional download in a variety of high-quality formats including lossless, and (of course) the satisfaction of directly supporting an artist they love.
Before buying, fans can stream tracks in full on Bandcamp only a few times before getting a dialog that prompts them to purchase the release. The default (and minimum) number of full plays before fans get this prompt is 3, but you can increase that limit (or disable it entirely) from the bottom of your Profile page.
You always get unlimited plays of your own tracks when you are logged into your artist account, so you won't get that purchase prompt unless you log out and stream your songs enough times. But, for the curious, here’s what the purchase prompt looks like.
First, consider that people generally want to get to know a piece of music before buying it, and very few people purchase tracks or albums that they haven’t heard in full at least once. One of the best ways to sell music is to let people hear it, fall in love with it, and come back to purchase it. Here’s some more on that philosophy.
If you'd still like to disable streams on certain tracks altogether, Optional Streaming is a Bandcamp Pro feature that will let you disable streaming on tracks of your choice. Once you’re Pro you’ll see a checkbox in the track editor labeled “enable streaming,” just above the download controls.