Help! I need a Cheap fix for this.

Welcome to GC!

Are you wanting to get grass growing there, or are you looking for something a bit more like a planter? You could make yourself a raised bed which would require some wood and then some soil to put in it - whether you would class that as cheap or not remains to be seen.

 

OK, I have quite a bit of recent experience with sheds, so hopefully can help a bit there - firstly, you want to have airflow under the shed to help keep it dry, so I sat mine up on breeze blocks (on their sides), spaced at fairly regular intervals under the bearers. Breeze blocks are as cheap as chips, so you could lay them out and then use bits of treated wood where needed between the breeze blocks and the bearers to level the shed up - that would mean that you won't have to spend money levelling the ground underneath the shed, as it would never be seen

Top tip - buy the best shed you can't afford (go for shiplap if you can, and as thick as you can) and take your time putting it up. I used Project Timber for mine, purely because you can spec the shed exactly as you want it.