Unless you're staying for more than a weekend, I would suggest leaving your car at home or in a parking lot on the mainland for $13-15 a day. Otherwise, bringing your car along on the ferry will cost you nearly $150 plus the roundtrip ferry cost of $17 per person. If you're only there for a couple days, you might as well just Uber/Lyft around. It kind of depends on where you stay. Oak Bluffs is the more happening part of MV, so if you're staying there, your rides will be quick and low-cost. But if you're staying in Vineyard Haven or another part a little further out and think you'll be traveling across the island to Oak Bluffs often for the night spots, then those trips will probably be around $25 one way. At that point, maybe you just want to bring your car. And there's the bus as well for $2.50, which I have also used. Hope this helps!