Maybe a Panasonic G5?

It's 16MP and can be had for around $400, and you could probably add the 45-150mm lens for another $200, but that still leaves no money for a fisheye. (Pany's is ~$600 and the 3rd party Samyang/Rokinon--which will be full manual; no AF, electronic aperture control, etc.--is $300.)

HTH - Mark