I am not familiar with those apps, so it is likely you will need to contact their respective developers for uninstallation instructions.
In general we must quit open apps before you can delete them. If you do not know if they are open or find yourself unable to quit them for whatever reason, restarting the Mac in "Safe Mode" will ensure they will not be running. You ought to be able to delete them while operating in that mode.
After deleting them, restart your Mac normally (not "Safe Mode") and they will cease to be active. You should then be able to purchase new versions.
For reference:
Delete or uninstall apps on Mac - Apple Support
Start up your Mac in safe mode - Apple Support
Contact a third-party vendor - Apple Support