I would get a mountain bike. If your getting into cycling your probably not totally sure of what you want to do with it yet. Well for under 50 dollars you can get a set of slicks (road tires) for your MTB bike which will allow you to go on road still fast. And you can change out tires to go on the trails. This way you can try what works best for you. Get a nice hardtail though, it will do better on the road. It wont be as light as a road bike, but say you want to go over that patch of grass, a road bike wont be too great for that either
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