You're going to have a hard time getting someone to do one professionally
for that budget.
However, doing it yourself, using Jing to record your screen, and iMovie to
stitch it together could get you to a passable product.
Do you have a PowerPoint deck with relevant visuals for the conceptual
pieces?
I would try scripting it yourself, and then recording you talking over the
relevant, static slides, and interleaved product screen captures.
Cut it
together with iMovie or similar (you're going to have to learn to do this
for product demo videos anyway), and use the stock music that comes with
those video editing suites.
It won't be the same as an epipheo video, but if you're pre-product market
fit, it's probably premature to invest in something with a crazy amount of
fit and finish.