What's the bus cost? How long does it take? Any tips?
About an hour and a half and it costs 1,200 Colones ($2.50 ish). You can use a Tica bus but you have to book it and stand on the highway etc. and its not worth it.
Walk across the border and take a bus to La Virgen for less than a dollar (Its 15 Cords but you may get a gringo price).
From La Virgen, bus 10 - 20 Cords or cab 30 Cords to SJdS.
Cab from the border to SJdS expect up to $20 per person but $10 is good.
Border: Have $12 exactly for entry to Nic and one dollar to enter the gate after that.
I'll give my best shot.
with a car?
What are the specifics?
See http://www.nicaliving.com/entering-leaving-nicaragua for this and so much more.
The test of our progress is not whether we add more to the abundance of those who have much, it is whether we provide enough for those who have too little
— Franklin Delano Roosevelt