S&SMODS is running a 20% off sale. Currently they have no coupon system on the site and only use PayPal. They told me that you need to email them:
sandsmods@aol.com
In your email tell them what you want. They will invoice your PayPal account for the adjusted price with the 20% off.
You can find everything they sell here:
http://www.sandsmods.com/