Orient your polar orbit perpendicular to the sun, burn to achieve Earth escape velocity approximately when you’re over the equator, and you’ll end up on an elliptical solar orbit in the same plane as Earth’s orbit. Burn the right amount and adjust the plane a bit and you’ll be in a Hohmann transfer to Mars.
What’s the added cost for that?
I know that the Shavit launches are all retrograde despite the geography allowing for a southward launch because transfer from polar orbit to LEO isn’t cost effective for their platform.
Polar is a kind of LEO, at least if it’s low polar. The burn from LEO to Mars transfer will be about the same regardless of whether you’re coming from an equatorial orbit or a properly-aligned polar orbit, so the added delta-v cost will be the speed of Earth’s rotation at the launch point, which you don’t get to use for a polar launch.
In terms of dollars, if you’re flying on a rocket with enough excess capacity anyway (as seems to be the case here), it’s free. If you’re not, then you’ll need to cut your payload or use a bigger rocket, which would be extremely expensive.
