Can I reuse glass bottles with plastic lids for homemade sauces?
Reusing the bottles shouldn´t be a problem as long as they can be cleaned properly.
But I wouldn`t use them for canning for two reasons:

Metal lids usually have a 'click' that ensures they keep the vacuum seal and allow you to check if it is still unbroken.
Some sorts of plastic are not meant to be heated and when cooking the bottles for canning there is a risk that some chemicals (e.g. BPA) diffuse to the food.