I want to send a thank you to a local government official. getting flowers delivered is like minimum $50 these days so fuck that. something like a gift card might be inappropriate for a government employee to accept.
If their boss was being a problem, make sure you don't tell them specific details about how the employee helped. Especially if the employee bent some rules or otherwise went above what they should have. It might get the employee in trouble.
I guess it depends on the specific laws of your country, but IMO gifts that have any real value save symbolics are off the table (even if not strictly illegal). I would just send a heartfelt letter expressing my gratitude. That would certainly make them feel very much appreciated!
Send a dozen donuts to be delivered first thing in the morning. Avoids the monetary limit and lets them be a hero for sharing the donuts with their coworkers.
Again I don't know about your local rules or what's available but since you were considering flowers and decided against them because of the price, my suggestion would be a nice thank you card and maybe a small tiny cheap succulent plant. They are hardy, easy to keep even on a desk and they cost like a cup of coffee or so.
I sent flowers to a different office as an apology, that and donuts are the only thing I can think of to get delivered. it seems like there's a gap in the middle there, a hole in the market that I could fill. something you could deliver that's better than donuts but not quite as dramatic as flowers