While it looks like it should be a relatively simple process, converting a nutted front hub to quick release can involve a number of pitfalls. The main trick is in picking the right matching front axle. It has to be the precise length to fit into your bikes fork without extending all the way through. It also has to have a thread pitch to match your hub's cones. (you can also swap cones, of course, but then you have find dust shields that will match your new cones and existing hub shell.)

If you have budget restrictions, by far the cheapest solution is to buy a 15 mm wrench to carry with you in the car. Might even be faster than fiddling with a QR.