Smart move! It is always best to make use of what you have for as long as possible. If you are happy with that sub now, you will be happy with it when its fixed, and a working driver won't go to the recycling center or the dump.
Keeping equipment functional for the long term is the most economic way to pursue this hobby.
Try and choose good gear, look after it and maintain it. That is the surest route to good long term satisfaction from superior equipment. And whatever else you do avoid junk. Quality pays dividends.