I am a firm believer in economies of scale. When I can, and when I will use it, I always buy large economy sizes.
I keep samples and sachets for when I travel, or I decant into small bottles, but at home most of my products are in big containers – either decanted into smaller ones or used as is.
I have lots of very long curly hair so I go through lots of conditioner. I only wash my hair once or twice a week but I condition it every day. As everyone with curly hair knows, when you sleep on it it goes all weird so I wet and condition it every day to get the curls back to normal.
My go-to brands are Redken and Kerastase and I usually buy them on special from lookfantastic.com or HQHair (both owned by The Hut Group). I am on their mailing lists so am mailed discounts twice a week (usually Wednesdays and weekends). They have free worldwide shipping and generally have 3 for 2 or buy one get one free offers so I stock up about three times a year.
You use far less Redken or Kerastase than you would a supermarket shampoo plus with the special offers, they do not cost much more.
And
they do large sizes!
I buy either 1000ml or 500ml – they last forever and the shipping is free (just keep each order to a limit of 2kg). 1000ml of conditioner is between £20 and £22 – and you usually get extra discount codes twice a week. Can’t beat that price!