https://www.theverge.com/2013/10/9/4821692/t-mobile-announce...
Just a regular prepaid SIM card, no strings attached. If you use it for just 1 month, no problem, just don't top it up. The SIM itself costs 10€.
This is far from the norm though, this company basically undercut everyone else and they had to lower their prices. The fun part is that they're actually better than most because they don't try to charge you random fees every few months.
They sell you a hotspot that works in 80+ countries with an eSIM. When you land you top up 500 MB of that countries data for a few dollars, which is usually enough to get me to the hotel and then out to a shop where locals buy SIMs. Depending on the device they have 1-2 extra SIM slots and you an hot swap between them.
There is an upfront cost and it doesn't quite meet your price point - but it gives you the flexibility to do a bit more shopping past airport rates.