What type of tie would suit a very dark purple shirt? (Formal, wedding)

Upcoming wedding in May, where exactly would I get a very dark purple (preferably silky?) shirt and a tie that matches it?

I've read that most of the time, a dark shirt and a light tie don't look too good most of the time, so how do I manage with a very dark purple shirt?

Price range is less than $120 for both the shirt and tie.