You can also hand draw or hand paint (HD or HP or HDHP on
ebay) the cachet. Some folks collect these and the art on them is what makes them more valuable.
A fellow in the UK makes beautiful painted cachets of GB stamps, has a web site, forget what it is, sorry. Search for First Day Covers and hand-drawn or hand-painted on Google I suppose.
I have attempted to make some in the same size as
Canada Post sells. It is a bit off from what is commercially available so I printed what I wanted on a 8-1/2 x 11 inch (or A4) piece of paper and make a template to fold the paper into the proper shape. It is kind of off a bit nut so am I so it works for me for a first attempt.

Having FDCs or event covers or just because I like it covers on regular sized envelopes, USA #6-3/4, UK A4) which the printer would take is a bonus.
Canada Post lets you send in your cover to be cancelled by the special first day cancel for 3 months I think, maybe less. The US has a similar program of sending the envelopes to the city of issue's post office. Not sure about the UK. Probably similar. Canada seems to copy Australia and the UK a bit.
Just to get a regular cancel on the day of issue is something that I imagine some people do. A commercially used cover, not an official fdc or mass produced. But, again, the aesthetics or looks of the cover affect it's value to someone else.
If that is of no concern and you just want to have fun then experiment away.
I think in the US anyway there are classes of these types of covers. A lot of people are making them.