BrowserStack is one of the best cloud-based testing platforms that allows users to use virtual machines and resources that can be used to run automated multiple browser testing of their applications on different operating systems and platforms. On the other hand, Sauce Labs also offers automated cloud-based testing that allows users to perform multiple browser compatibility tests on different platforms and operating systems.
Their services are usually paid for except if you sign in for a free trial. For BrowserStack, before you can have access to their basic plan and another one that allows you to have unlimited screenshots and live browser testing, you will need to pay $12.50 and $39 per month, respectively. There is also another plan for Android and iOS devices that will cost you $199 per month.
For Sauce Labs, their prices for all available plans seem to be a bit higher compared to that of BrowserStack. Another difference is that Sauce Labs is quite easy to use compared to BrowserStack due to the fact that it is more stable than BrowserStack.