You are going to need these to fly your traction kite. There are various different types and makes on the market - mine are Flexifoil ones - quite thick and padded and have stood a couple of years hard use.
The main considerations are the handle thickness, how much padding, and how much they cost. It's best to try holding a few to see how comfortable they feel - given you are going to be holding on verytightly something comfortable is going to be best.
Cost: Expect to pay around £15 for a decent set of handles (unless your traction kite comes with them of course!)