@dbstudios - You may ultimately decide this is a good idea... but I think it's a stretch.
It would be hard to find a more over-stimulated group of people than folks watching a parade. Marching bands, dancers, glitter, pom poms... it's probably 90 minutes of one spectacle after another. Standing out in that crowd is difficult, being memorable is almost impossible. Giveaways could help, but it's a total crap shoot as to whether any of those spectators are making a buying decision on a DJ in the next 36 months.
I prefer an avenue where I can be a big fish in a small pond. For example... I have luck with boutique bridal shows. 1 vendor of each type, 20-50 couples... absolute sweet spot. I want more attention from less people, not the other way around when I do my marketing. Sometimes you have to do some macro brand building, but I think a parade is a really tough way to do it.
Here would be an alternative... Around here we have a number of mixed use Retail/Dining/Living sort of developments that have gone in. They host events constantly to keep people engaged and having fun in the space, which ultimately benefits all of the retailers. For example this is what's on the calendar right now:
Approach a venue like this about doing some sort of kids event... daytime dance party, glow sticks at night, whatever... It can be 60-90 minutes, shows off your DJing, shows off your crowed interaction... and you compete against absolutely nobody. You get undivided attention (and thanks!) from parents, and you get to showcase in a public place. It would probably cost you much less.
If you want to take that up another notch, get a charity involved. Sell the glow sticks to benefit the charity. Take donations for them as well. And ask the charity to promote the event with you. It might even help you get the event booked if you can sell it as a "Fun-Fundraiser" for a well qualified charity.
You can brand glowsticks, give away frisbees, use any of that swag as giveaways during an event like that and it totally makes sense. I think you'd get a heck-of-a-lot more bang for your buck doing something of that nature versus loading a flatbed and getting 30 seconds of attention from parade-goers.