Since you are trying to do something original, nobody can give you a definitive answer.
I'm going to assume the question means you really don't want to develop your untreated voice, and you don't mind sounding like a robot, having unclear lyrics etc.
I would recommend buying or borrowing a budget guitar multi-FX pedal - or a computer application like GarageBand or Guitar Rig. Try out the presets, but more importantly, get stuck into editing patches yourself, auditioning different effects and parameters.
There are pedals for under $50 which would be suitable for this exercise.
The voice has a similar frequency range to a guitar, so the effects should work. You may need a pre-amp between your microphone and the FX pedal, to get a loud enough signal into it. Most modern multi-FX pedals accept both instrument-level and line-level inputs.
Effects that may be especially effective on voice include:
- delay - long delays in time with the tempo are quite common in rock/pop/dance music. So are slapback delays
- reverb - very common on vocals - more traditional than your aspirations perhaps, if I read the question right.
- phaser/flanging - these effects used on vocals have precedent in psychedelic music
- chorus - either used subtly to simulate multiple voices, or heavily as an artificial sounding effect
- overdrive/distortion - that "through a loudhailer" vocal effect
- pitch shift/harmoniser - probably horrible, but you can try it
Once you've experimented and have a firmer idea of what you want to achieve, you can think about whether the multi-FX pedal is the right way to do it in the long run.