There was two different types of EFX.
The plastic PCR version, was about 300$ when came out, and was the best and more accurate option for a ?*low*? budget.
And the fiberglass Limited/Legend which were about 650$ at the time.
But you would certainly pay insane prices nowadays on secondary market.
Anyway you can’t go wrong with the Quasi!
For a more ?*modest*? budget I would highly recommend the Darth Ugly. ( same maker than Quasimodo):
Certainly the best option in this price range.
( Darth Ugly: 550$ / Quasi: 850$ ).
Look also at the New Image Prop replica Vader. It seems a pretty decent helmet for the price, full fiberglass.
Got their Scout trooper helmet and it’s really great.
Everything else mentioned previously ( CFO, TM, Mike Warren, JMC...) if I remember correctly is 800 and more.
I did not mentioned Anovos because of their business model. It’s a nightmare and a joke.
Eventually if you can have it from a second hand which has already it in stock why not.