Go to thrift stores. People die and and retire every day. I've bought many very expensive ties (Brooks Brothers, Burberry, etc... .) for $3 a piece at thrift stores. Dress shirts are more hit or miss, because guys will food chain their shirts, but JC Penney's sells a very good dress shirt for less than $30. Also Joseph Banks always has shirts on sale. I just bought three french cuff top of the line shirts for $90 (regularly $90 a piece).
I intend to be demonstrating some products that tend to be very messy and permanent. $30 shirts aren’t on my radar nor more expensive ones.