Unless you stumbled on this place for sale, and had nothing but a FSBO agreement with the seller, who was clueless in real estate matters, something is very wrong. In my state, and I assume most others, you are to be provided with a full seller's disclosure document, available for you to review before making an offer. I would expect that the seller, and any realtor involved, would make it VERY clear that the street is privately owned and maintained. Since, it is often a deal breaker, and tremendous fuel for the fire, if the buyer decided to file suit, and/or charges with a state RE board.
As for buying the place, it's simple, no way in hell, period. The average homeowner doesn't have a clue as to how horrifically expensive it is to repave a street. I almost pulled the trigger on a detached single on acreage, but I was concerned about a very long driveway and several large parking areas that would need to be repaved in the next decade, or so. I called a buddy in, who does large paving jobs. He did the math, and put the current value of repaving the whole thing at $35K. Shared roads are a disaster, far too often. The road gets near the end of it's service life and the patching begins. Now the few bucks a year in plowing fees turns into a few hundred or a thousand. Pretty soon, one responsible party says they can't or won't contribute. Time go by until the value of all the homes are degrading, since the road outside your door looks like the road to Bagdad. Now, it's time to mill and resurface, and everybody needs to chip in $12-15K. Yea, good luck with that.
Don't walk, RUN, and don't look back. $700 was a cheap lesson in this case. If you were dealing with a realtor, I would hand them a bill for $700, and tell then you are filing a complain with the state realtor's board if you're not paid promptly, since you should of been made aware of this before you even thought of making an offer.