You can rent a bicycle. There were two rental shops at the beach in Santa Monica (not far from Venice). They have different bicycles (2 or 3 wheels type). You need to have a credit card or not :). I didn't had credit card and I still managed to rent. Don't get discouraged by it. One of those rental places won't even talk to you if you don't have a credit card. But at the other one (go around and you'll know which one it is) there is this nice guy. All you need is to leave a deposit. It's 100USD which you get back when you return the bike. You can also buy a bike which is about 100USD (at this place and it's used). I don't remeber the ratings because I rented out the bike for a whole day and that was 20USD. They close around 7:30pm but you can return the bike early in the morning next day and you don't pay extra. Remember with the bike you get a helmet and a locker (ask if you don't get it right away because they may froget to give it to you!)
Getting around. Best is to move on the pathway at they beach. Its there for the bicycles and no cars there :) but remeber there are fellow users!!!!! so be nice and careful plus some pedestrians walk into it to! Don't run over them!
You can't get everywhere by this pathway. Sometimes to get to some places you need to use normal roads. Cars are usually no danger. There are so little bicycles that most (but not all!) car drivers look as if they are affraid of you and pass slowly near you. The only way I could bicycle my way to Malibu was by using the Coastal Highway. It's dangerous if no traffice but you can manage it.
You can use bus to transport yourself + the bike but be sure to know how to use those hangers on the bus. I was lucky enough that the bus driver helped me when I said that I don't know how and in that case I won't take the bus. But he wasn't happy about it!
We took the Bus from where we stayed in North Hollywood all the way to venice beachand back. We had to make 2 or 3 transfers, but the total cost was under $2.00. A taxi ride would have cost in excess of $60.00, so you can see the savings.
Man, when you get there, walk or rollerblade or rollerskate or skateboard or bicycle. I saw all of these modes of transportation in abundance. Walking isn't bad, and let's you enjoy the boardwalk at your leisure, and without having to worry about crashing when you want to enter a store. :-)
When in Venice... rollerblades is a great way to get around Venice, on the boardwalk and off. Just be careful and stay away from the cars. On the boardwalk, especially on weekends, you may find people doing tricks on their blades or doing some sort of rollerblade line-dancing to music coming out of giant boom boxes wheeled in by the hard-core enthusiasts.