"The tickets are really cheap."
Translation:Tha na tiocaidean gu math saor.
For the same reason as you say really cheap not cheap really. Adverbs go in front of adjectives.
It is of course a big mistake to assume that Gaelic word order is the same as English but this rule does appear to apply to both. I can't think of any exceptions in either language. Maybe there are some?
This is the general pattern in this part of the world with our neighbours the Irish, the Germans and the French agreeing with us. It is just the Welsh (and maybe other Brythonic languages?) who put a few adverbs after the adjective: da iawn = good very.