Possibly a bit niche, but a great deal on Gtechniq CSL ceramic coating. Warranted up to 5 years for accredited installs, normally retailing around $155 for 30mL.
Listed as $76.06 ea but the 20% off when you buy 2 brings it down to $60.85 per 30mL bottle (about 60% off Australian retail).
How much would you need for one average sized sedan? Can be applied by the average do-it-yourselfer with a few tools?