They're not cheap unfortunately. There are also braille slates if the refreshable braille displays are currently out of your price range.
The Orbit 20 is the least expensive option I can think of off the top of my head in the US and it's
$1.
I would definitely be putting money away for one in the future if you currently can't afford one. A lot of blind/VI people can't read braille very well (or at all) due to the over reliance on voice dictation in modern operating systems. I have zero problems with voice dictation software (and it's getting better every day) but reading is an important skill for the blind/VI just as much as it is for sighted people.
Have you learned grade 1 &or grade 2 braille yet?