Here is a guide on how to make your own Ferric Chloride etchant. It’s a relatively simple process that only requires some iron, hydrochloric acid, and air. As the process uses acids please be careful, and do this only if you feel comfortable with it.
Get 20g of iron. This can be in the form of nails or steel wool. It’s best to use iron that’s rusting, that indicates it doesn’t have other metals like zinc or chromium that’s normally used to prevent rust. To the iron add 100mL of water and 100mL of 12M hydrochloric acid. The iron will start reacting with the acid to produce hydrogen gas and ferrous chloride. If the reaction is proceeding too slowly for your liking you can heat up the mixture. A flask of cold water on top is useful to reduce evaporative losses.
Side note: If you already have access to hydrochloric acid and hydrogen peroxide you might be better off just using that for etching. Here is an instructible on how to mix it up, and why it might be better then Ferric Chloride.