Advice on good show clothes?

This will be my first year seriously showing (before i just went to a few little shows for the fun of it). I will be going to a variety of shows from mini schooling shows to rated 3 days. I'll be showing in wtc pleasure/equitation, low equitation over fences and green horse (on a few different horses) I have a helmet, hunt coat, boots, and one show shirt. I would like to get a few more shirts and some suitable breeches (i have 2 black, one blue, and one plaid only so i cant obviously wear those). What relatively inexpensive shirts and breeches would you recommend? also what is a nice show pad i can buy for my horses? Thanks!