I've worked with DB people and running lines under driveways for telco and cableco is BIG business and they will not find your request to bury fiber or cat5 to be even remotely unusual.

The bad news about directional boring is they usually want "like a kilobuck" just to show up. Its a lot of heavy equipment and a lot of dudes to operate it all.

The good news is if they're already down the road they'll come by and bore for like $20/foot because its a small job (usually they only charge $10/foot for long runs)

Permitting depends a lot on where you live, some places treat it as a cash cow and they will brutally milk you, others don't require a permit at all. The equipment takes up a fair amount of space on each side, probably more than you'd expect. Scheduling is like dealing with an arborist. "OMG I need this partially collapsed tree removed immediately its an emergency I have homeowners insurance please arrive in the next hour" well thats multiple kilobucks "Meh please remove this tree sometime and I don't care when" well thats like $250, probably less if cash.

I've seen people spend thousands of dollars on DB or crazy laser/wireless comm gear to avoid spending hundreds of dollars on a stone mason. Try not to pay someone to DB under a stone wall, its usually cheaper to hire a stone mason twice and he will leave the wall in better condition than before you started. All masonry is temporary unless its maintained. Similar logic might apply to driveways, most concrete cracks so if you're hiring a guy to fix the crack you may want to bury a conduit before he fixes it. Replacing an entire driveway is expensive, replacing a sidewalk sized path is surprisingly cheap. If you want sidewalk poured (like for a walkway in your garden or around a swimming pool) its about $50/foot and a driveway would have to be thicker and better prepped, but the section could be narrower than a sidewalk. The point being don't accept a DB bid over $50/ft because its cheaper to replace the concrete at $50/ft.