I have seen many tutorials with effects that I can't see after paying the subscription.
How can I use them?
S_Shake is a BorisFX Sapphire plugin. Are you saying you have bought Sapphire, and S_Shake isn't working? If so, you need to contact BorisFX
@tmiranda You can use them if you purchase BorisFX Sapphire. It's a different product that does not come with Vegas Pro. On the other hand as MikeS pointed out, if you already have it, but its just not showing up, you need to contact them.
With Vegas Pro's native 'Film Effects' VFX, you can select 'Jitter' in the 'Type' field and then select the amount of jitter using the slider underneath that field.