I am getting ready to add a shop to my website. It will sell campers. I want people to be able to select the base model (sz) and then add optional items like tool boxes, hitch sz, etc. At "checkout" instead of collecting the full price, we just want to collect 10% of the total due. I think this can be done with Woocommerce. Is there a better way to do this? Any suggestions appreciated! Thanks!!!