Playground vs Dev Org Creation, Cost, and Usage

Hi everyone!

I was hoping to get some guidance as I’m very new to Salesforce. I am a hands-on learner and can’t seem to grasp Salesforce concepts unless I go through them for real world applications. I am completing the hands-on activities at the end of modules but soon forget the information since they apply to the instance of the module and not to anything I can connect to in my life. I was thinking of creating my own instance for either my current job to see how it would fit or for my personal life (planning a trip to Europe in April!). From what I’m seeing, I can create my own Playground and play around in there but I do also keep seeing Dev Orgs and was wondering if that was something I was able to create for free or if that was only available through a paid Salesforce license. If anybody can offer some guidance on how the Dev Org differs from the Playground in terms of creating one, pricing, and user-friendliness, that would be amazing!