Are you clearing out your toy cupboards? If your little ones are no longer playing with the old Play-Doh, then use it for trying out casting ideas before you buy expensive moulding products.
I work in concrete myself, and when If want to reproduce an object in concrete, I need to make a mould of it. You can invest in a silicon or rubber material sold specifically for this purpose. They are fantastic! Often easy to use and you get a smooth results, true to the original. But…also a bit pricey. Prices differ, but I paid £30 for a litre of the product that I chose.
So a fun and easy way to try out your ideas before hand, or to make cute little objects that you only want the one example of, is to make imprints in Play-Doh.
Use a small box to keep the clay in place and press your object into it. Remove it carefully and then fill the depressions with concrete.
The results will most probably be a little skew, and the surface rough and uneven. But it is instant and very cheap!