There's also the double strollers you can snap your twin car seats into.
I highly recommend getting at the very least a double stroller. They can be pricey but there's nothing wrong with buying used. It will make it manageable when you have to take the kiddos out and about!
Oh my goodness! We'll let me first say good luck!! And I would try like craigslist and stuff to see if you can find one
Babies r us Has strollers for multiples there expensive but are worth looking into