Patricia, at Rural Revolution, has a good post on cheap prepping.
Stop by your local grocery store (Walmart) or bakery and see if they have any plastic buckets (food grade) to get rid of.
Back in our naïve days of preparing for Y2K, Don and I bit the bullet and bought 24 five-gallon buckets with screw-on gasketed lids. These have been superb buckets and we still use them, but they were expensive. Bakery buckets are a far better deal.
Bakery buckets are quite literally a prepper’s best friend. For the last couple of years, I’ve made it a policy to stop at our local grocery store’s bakery department and inquire about buckets. Sometimes there aren’t any available (others beat me to them), sometimes there’s only one or two, and sometimes I hit the jackpot.