Try Craft Pro & Plugins Before Buying
If you would like to try out Craft Pro and any paid plugins in the Plugin Store before buying, you can do so by running your site from any domain that Craft does not consider to be a public domain (see How do we determine Craft is running on a public domain? for more info).
Common examples of domains that would work include:
If you are moving an existing site to a new non-public domain from a different local host name, you will need to clear your data caches from the Clear Caches tool on the Settings page before Craft will realize that the host name has changed.
Craft won’t automatically upgrade itself; you will still have to do that manually. Go to the plugin store (or click the "Solo" button at the bottom of the left sidebar) the click "Upgrade Craft CMS."
Then click the "Try for free" button under the Pro edition.
Craft will immediately swap editions. No credit card info required.
You will then be able to play with your upgraded Craft edition indefinitely, as long as you’re running the site from the same non-public host name.
All paid Plugins in the Plugin store will follow Craft's lead. This means that once Craft is in trial mode, you can try out any plugin in the store for free.
If you deploy your site before purchasing the upgraded Craft edition, your website will work normally, however Craft will ask you to either downgrade your license or purchase the upgraded license when you access the Control Panel.