I use an XBox controller. It's a good middle ground between keyboard and HOTAS. Gives you plenty of choice about how to bind things, it's comfy, and it is small so doesn't get in the way like a HOTAS when not in use. On top of this, it's <£30, but doesn't have the huge deadzones associated with a cheap stick.
For instance I have roll and pitch on left stick, yaw on right, and throttle up/down on the triggers. Weapons, zoom, countermeasures, action menu, landing gear, etc go on the rest. Unfortunately when I last looked I couldn't map radio controls to it, so if I'm in a particularly difficult manoeuvre I can't answer the radio easily, as it requires some hand acrobatics to use the keyboard at the same time!