Originally Posted by daftboy

Agree this is a good idea for a thread (sub €75 a bit trickier, but anyway...). Some data points below

DUB - an increasingly expensive market in general, Maldron and Radisson on campus (not connected), other options a shuttle away, but as easy to stay in the city really
CPH - Hilton attached to terminal, not cheap but Honors points can help
MAD - Ibis a relatively short shuttle ride from T4, but stops at other terminals out and inbound
AMS - seconding Citizen M; Hampton by Hilton is one stop on train and a 5 min walk (think there's also a shuttle)
LIS - not sure of actual options nearby, but airport is v central and getting downtown on metro or via taxi is very easy