If you want the cheapest and most casual cufflinks, you go for silk knots. Parisian shirtmakers Charvet are credited with inventing them in 1904, but these days you can get them almost anywhere. Modern silk knots are made out of manmade fabrics over an elasticated inner, which help them stretch and move. They're a great look, but a little too casual for most situations.
In come the Gunmetal Knot Cufflinks. They're a great balance between the casual style of a traditional silk knot and the versatile functionality of metal cufflinks. Slightly darker than plain steel, these cufflinks are a great way to inject a little style and class into your shirt and suit without being too flashy.