Doing it in a studio has some problems with how convincing it will look, especially under the scrutiny of the tin foil hat people. You will want shots of the rocket landing from a camera attached to the rocket. I don't think todays CGI will hold up, mainly because it will look similar to all the CGI we've been seeing in films like Interstellar etc today.
My idea would be to land on the moon and then post process the footage to make the surface look red. There are areas of the moon that look just like the surface of mars, finding the right one might require sending out a probe in front. It would be easy to film because you just act like it actually is Mars and do everything the exact same way. 900
Post processing the footage to make the surface red and maybe haze out the sky a little would be relatively cheap and easy too.
With the same technology they used to land on the moon before, there are probably ways to cut corners and do it relatively cheap. Compared to landing on Mars you will probably save billions.
Edit: Just to add a few more details to make the hoax more convincing. As I stated in the comments to this answer, people will want to see the rocket leaving the Earths atmosphere and re-entering, not an easy way around this than actually doing it.
Once behind the moon, you split the rocket in half and send half of it to Mars, where it will go behind Mars and crash into the surface (hopefully won't be discovered for 20 years). This will give astronomers the impression that you went and landed behind Mars.
The half of the rocket with astronauts in will land on the "dark" side of the moon (which isn't actually dark). They will film the landing, and edit it on their trusty laptops which they took along with them (or send it encrypted back to Earth if they're not good at Adobe After-Effects).
When the Mars-bound rocket gets to Mars, they send the edited footage unencrypted back to Earth for the viewers back home. They then take off from the moon and head back to Earth and do everything as normal. 500