there is no way two trays with FEP is cheaper than just FEP....
Here's the Amazon link for the Anycubic FEP replacements: https://www.amazon.com/dp/B08PPDJJM1
$45.99 for two new FEP screens, nothing else.
The Sovol two pack which is two vats with replaceable FEP is here:
https://www.amazon.com/dp/B08G82HSTD
$43.99 for two new aluminum vats with FEP and covers.
I'm going to go the Sovol route so I can replace just the FEP in the future. Their five-pack of FEP replacement sheets is $18.99 here: https://www.amazon.com/gp/product/B091TDV8XL