On the William Optic website the price (direct with free world wide shipping) is $698 USD.
https://williamoptics.com/redcat-51
Available early March.
It has a 48mm inbuilt filter slot, in the rotator I think. It's worth having a look at there.
And Dunk is right, it is more expensive than the FPL-53 Doublet in the Astro-tech and TS 60mm scopes, but it would seem you don't need to buy a flattener.