If you both have bikes, a cycling trip can be great fun and great exercise. Get out and see parts of your local area from a perspective you rarely see. Or throw the bikes into your vehicle and explore an entirely new area. Either way, a bike ride makes for an excellent date with minimal costs involved.
It’s important to make sure you plan the bike ride with your and your partner’s fitness level in mind. There is nothing worse than a biking trip that exhausts the two of you beyond the point of being fun. Plan short biking trips to begin and then longer and more difficult ones as you learn both of your endurance.
Also check the weather before trying a date like this. Again, there is nothing worse than a bike ride where you get cold and wet along the way or where the wind is so strong that you don’t feel like you’re making any headway while biking. Biking can be an excellent inexpensive date, but you do need to do some basic planning to make it a success.