Sorry to hear about your iron levels. I've been there before an it's not fun.
Hope you feel better soon,
As for filling a detolf for cheap or free I suggest recycling. I have a whole playlist on my youtube channel which might give you some ideas.
Using Recycling - YouTube
My other top tip is get some jute or sisal string, approx a £1 or £2 from garden centres/wilkos and you can make so many hanging boredom breakers with that.