Very low-quiescent (<2mA), 5V, simple "speaker" driver
If you want to get 150mA with a 30 ohm coil (the resistance will increase with temperature) you'll need no more than a couple ohms switch resistance. 

One way to get that would be to use two complimentary pairs of MOSFETs in an H-bridge configuration. For example, the DMHC3025LSD contains all four transistors and is less than 0.2 ohm for the total high+low switch resistance. To get a fairly clean 1kHz you'd need something like 25kHz-50kHz minimum PWM frequency, so you'd probably need a gate driver for the MOSFETs rather than being able to drive them directly from a microcontroller PWM.

If you drive them both high or both low, the current consumption will be minimal (microamperes). For an analog type output you would drive them with complimentary PWM waveforms to get bipolar output. It might be difficult to get much fidelity unless you're using close to full amplitude. If the inductance of the coil isn't enough to smooth the waveform at the PWM frequency you could add an LC filter, but that will affect the 'digital' waveforms too.