Valeton Dapper Mini / Mini Effect Strip (with 9V power supply)

Love it! It small and will fit in gigbag/case pouch/compartment.
It has almost everything that any bassist needs to build good sound in any style. Very visible on pedalboard (if you need a pedal board with this set effects) thanks to bright knobs.
The preamp section sounds just great, chorus is very delicate, compressor is OK, octave is also nice, envelope (with fuzz if needed) works like old Q-trons and average tuner (not a Peterson but still useful).
A phones output would be a good add to the unit but that's not an issue.
An alternative would be Tech21 Sansamp/FlyRig but that would be in another budget.