If you want to decrease the amount of money you spend on dry cleaning, simply buy clothes that don't require special treatment in the first place. It's as easy as checking the label and deciding you can pass on an item knowing how much hassle and cash it'll cost you down the line.
But if you already have a closet full of dry-clean-only clothing, or absolutely must have a new item tagged with those dreaded words, then there are some workarounds. For example, you can buy an appliance or other DIY product to do your dry cleaning at home. If even that's too much, you can try gently hand washing items with a mixture of ingredients (say cold water and baby shampoo, or dish soap) to clean clothes that demand dry cleaning, while keeping in mind the fact that manufacturers often err on the side of caution. Just test the mix on a small spot that's not wildly noticeable before you go for the whole garment, and be warned: There are risks depending on factors like what type of fabric you're dealing with, whether there are stains and whether there is beading or lace sewn in. If an item is important to you, consult a dry cleaner; an aging work shirt is one thing, your baby's baptismal gown quite another.
If you do decide you must go to a professional, shop around for dry cleaners and look for low prices (although be warned: It's a sliding scale and you might be sacrificing quality and customer service). You can also try to negotiate your price; with any luck it's a slow time of year and they'll take you up on it.