Whoever owns the CL9 and corolla (assuming your car is parked home and those belong to other members in the house), convince them to invest on good waxes (show them a few pics) and then you do it on their cars as well as yours
Just kidding...
My mentality (and thats just mine) towards spending in this area and convincing others (and trust me i've convinced MANY) is that majority of the cars we see on this forum start from 5-7 lacs+. You can get quality wax starter kit (shampoo,towel,wax etc) around 5-7K which is 1% of the cars worth. This product set would last you atleast 1.5 years easily.
Our entire used car market runs on exterior condition of the cars. The better the exterior the higher its price among the siblings. Even if the car gets scratched/bumped/dented, we prefer not to get it repaired so as to keep the car in genuine condition. Just saying thats how the market works here.
Tu phir atleast 1% kharcha kerna tu banta hay boss for better looks and better protection of car 
But yeah, khayal rahay k @ahmad_yar ya phir @durrani_45 ki tarha detailing ki latt mat laga lena (as in the song 'mujhay tu teri latt lag gayi'
, warna kharcha 100% of the cars worth ho jayega 