Upgrade advice: Add more ram or sata ssd ?

[xHiqhAim]

Budget (including currency): about 500 Egyptian pounds ( about 30$ )

Country: Egypt

Games, programs or workloads that it will be used for: E-Sports gaming @ 1080p 60HZ

Other details (existing parts lists, whether any peripherals are needed, what you're upgrading from, when you're going to buy, what resolution and refresh rate you want to play at)

Existing part list: - CPU : Ryzen 5 3400g

                           - GPU : AMD Rx 570 

                           - Ram : Gskill  1 X 8 gb @ 3000 mhz CL 16 single channel

                           - Storage : 500 GB HDD - No ssd.

I am sorry if this is going to be a bit long. At first i built the pc with  the APU  about a year ago and  I was going to add more ram once prices go down a bit to get more fps by dual channel. Then recently my cousin gave me  his rx 570. Now i am puzzled. Should i buy another 8gb ram stick ( 35-40$) or buy a sata ssd ( kingstone A400 240 gb costs about 30$) ?

Sorry for bad english and thanks in advance

[WhitetailAni]

Add another RAM stock.

[Levent]

SSD will have the most noticeable impact. You will benefit from both but my vote is on SSD.

[ProjectBox153]

I would definitely get an SSD first. 8GB of RAM is fine, even if it's running in single channel. An SSD will make the computer a lot faster overall. 

[Quackers101]

a decent SSD for speed, you don't have ram in dual channel so another will help with FPS.