My reggie is already recession proof.
Water...no change there...I try to skip rinsing on days that we have a ban (I think it's tues and thurs) since I know I use a lot of water just standing under the shower head for no reason.
Castor oil...it's like 5$ a bottle. I buy two bottles a month at the most.
I don't really use anything else. I still have a whole bunch of coconut oil from a whole foods sale a few months back. If I feel the need to DC I just grab some kitchen stuff (honey, olive oil, etc.). I wash my hair with baking soda or my regular body soap (I use all natural glycerin or olive oil soaps).
I think that every regimen can be recession proof when you realize that there's always an alternative to expensive products. Though, many of the salon quality products are super concentrated so they do last a long time, which is a plus.
Also, most of the stuff people use is extra. I mean do you really need a regular conditioner, DC, leave-in, and moisturizer? Nope. If you buy a salon quality DC, you can actually use it for all of those things. I know Butterfly08 (I think that's the right one, there's too many butterfly screenames on here) who is relaxed and highlighted leaves in her regular conditioners. I'm pretty sure she said she uses Redken Butter Treat as a moisturizer. (Someone correct me if I'm wrong.)
Anyway, I used to take my Giovanni Deep Moisture conditioner, add water, and a bit of baking soda to cowash. I'd use it straight to DC. Add some water and then I'd leave it in. Same with my Oyin conditioner.
Just spend your money wisely. Make your products multi-task. And use cheaper things to make them stretch like baking soda, oils, water, or TJ Nourish Spa (it's only 3 bucks!) or another cheap conditioner.