All depends on the quality of the components you have. Replacing spokes is pretty easy but not if you've never done it. The $40 wheels are pretty crude but if that is what your local shop is recommending, perhaps they've made a judgement as to what you have now. Once several spokes have broken on a cheap wheel set it usually is time for some serious replacing. ON THE OTHER HAND building a wheel and having it work is pure joy! Be prepared for some frustration along the way. There are tons of videos showing how to get started. You could buy the cheap wheel and then have the time to play around with the old one.