Where did you get that price quote? I replaced all the stickers on the transom for around $30-$35 for factory stickers direct from the dealership.
"Wakeboard Edition", "MasterCraft", and "Towboat of the X-Games" all came one one sheet for that price.
I am not quite sure of the decals on the side you are taking about, but if its the X-Star graphics then I'm sure those are going to cost quite a bit more.
If you get a nice straight pic that's squared up, you could photoshop the letters out and take it to a signmaker to have it cut out custom, but I think you would end up paying about the same and be out the photoshop time.
For what its worth, I will not be replacing these stickers a second time, they get all torn up with putting on boards and surfing and such. I am going to cover the back with Gator-Grip or Hydro-Turf, just not sure which one yet.