Saddleseat Vests?

[Arya]

I am a hunt seat rider and have been riding since I was a kid. I just started working with and retraining this horse at my barn who only rides saddleseat and we plan on showing. The thing is I have no idea about the saddle seat attire. My trainer said to get kentucky jodphurs, a tie, vest, button down shirt and saddleseat coat. I looked online and the saddleseat vest looks the same as a normal boys vest. Can I get one of those insead of spending a ton on money on a saddleseat vest? Also where can I get a good pair of kentucky jodphurs? Do you know any good sites? Thanks so much.