Travis, paravanes tend not be be regularly available. You have to hunt around "proper" tackle stores. There are also several types. A common one, from which I have steered clear has a very large lead weight. They are usually blue or red. Might as well use a downrigger properly if you're going to use anything so heavy.
There is a Scandinavian one called Stim that is a good size but is very expensive. I have seen clones and bought one, but snagged it on my first outing so can't report how good they are.
Probably the most common, and the one that I have used most is the blue-line paravane, made in South Australia. This looks like a paper dart, only upside down. Comes in two colours, yellow and green. Yellow for small lures/baits, green for big ones. Eg small hbs versus whole squid. They sink naturally which helps when you're starting from a standing position but only have a small weight up front so are easy to manage out of the water.
Just remember my recent disaster involving a paravane. I was trolling with it, stopped to cast, hooked up and had to move. This meant I had to manage a hooked fish and the drag of the paravane while trying to paddle away. I stuffed up and the rod with the paravane went into the drink dragging other stuff with it. Fortunately the rod was leashed and all I lost was my net.
Biggest problem with a paravane is that it is inline, meaning that you tie the mainline to one swivel attached to the paravane and the leader to another. When you hookup, the pull of the fish is meant to cause the paravane to plane upwards but it is still a drag. That is why I will be experimenting to see if I can use it like a downrigger, releasing when I hookup.
