This shirt pattern, called a graph check because it resembles graph paper, is one of the more versatile patterns for dress shirts.  It is more interesting than a solid, but small enough to combine well with a wide range of other patterned items.

Suit: Southwick, thrifted, $8
Shirt: Borrelli, thrifted, $3
Tie: Kountz & Rider, trade, $0
Shoes: Johnston & Murphy, thrifted, $12

Total: $23
If I’d paid retail prices: At least $1300