Its not so far away! The Fourth of July is probably the most frugal of holidays - or it could be, anyway. If yours is filled with expensive carnival rides and even more expensive fireworks, it might not be.
Those two things are tradition for many families, so I won't tell you to forget them, but I will tell you to use common sense when paying for them. Buy a "bracelet" if they sell them, to get cheaper rides at the carnival and go easy on the fireworks. Extravagance doesn't always equal wow power.
Other than that, how can you save when celebrating Independence Day?
Keep a look out for sales on hotdogs and the fixings. Stock up if you can. Condiments keep a very long time, buns can be frozen and wieners freeze as well.
Ground beef should be on sale just before the Fourth, too, and it freezes even better. Think about all the cookouts you can have for less if you find a good sale.
Watermelon is ripe and ready about that time. If you really like it, go ahead and buy an extra one when the price is low. You can freeze the flesh in balls or slices, or you can make a drink from it by pureeing it in your blender and freeze that.
Fried chicken? Forget the deli and make your own. BUT... if you go to the deli, go a few days before, late in the day and you might find chicken marked down. It's fine, but you can freeze it if it's more than a few days until you need it.
Other than food, go to the parade and local free firework displays. Have a picnic at the park or in your own back yard if the park is too crowded. Get together with friends or family for a round of horseshoes or baseball or tag.
Have fun doing and being instead of spending and you will truly celebrate the day.