(1) The link that you provided goes to the Altohorn-Mellophone section. Are you looking for this type of horn for under $200 or a trumpet? If it is a trumpet, there are obviously a LOT of choices on their site. I looked through briefly and many of the trumpets for under $200 would be great for what you want to do, except....
(2) You said you prefer silver. That changes the equation. First, I wonder why you prefer silver for marching. You are a long ways from the audience in the middle of a large group of marchers. No one will be able to tell the color of the horn. Second, as you will note, that choice greatly limits the selection that you have. There were a couple of Kings that are nickel-plated in the $200 range but not much else.
If you drop the silver preference, then many of the trumpets in the Olds, Reynolds, King, Conn and others for $200 or less appear to be excellent choices. These brands have been the staple of marching bands for 100 years so you probably can't go wrong if you ask the seller for some additional details to ensure that it is playable when you receive it (I saw a couple with missing water valves or other minor issues that would need repair work before being playable).
Have fun shopping.