1. Drink less so you have to brew less.
2. Brew more than you can drink.
3. Find cost cutting techniques.
Everybody has hit on #2 so I won't touch on it further. #1 is obvious, but as you may or may not have already discovered, brewing makes you want to enjoy your beer frequently which means you will drink a lot. There may be some health reasons (e.g. weight) why you may want to limit your drinking. Alternatively, you may be comfortable with the amount you drink, in which case you will have to accept that one way or another you are going to expend cash on beer/alcohol.
Ok, so on to #3. Extract is a very expensive way to brew. I know people will point out the equipment costs with all grain but you don't have to constantly upgrade or buy expensive equipment. You can do BIAB techniques for the cost of a paint straining bag and a second kettle (if you don't already have one). Even the igloo cooler route is not very expensive and over time you will recover costs. (I am not hating on extract brewing -- just looking at the cost.)
Lots of brewers (myself included) like to make big beers, special brews, etc. that add expense. While there's nothing wrong with making that 200 IBU RIS with oak, cherries, fifteen yeast strains and then soured for 20 years, you probably don't need to drink something so elaborate all the time. Mixing in session beers into your pipeline will help lower expenses.
Yeast washing will help lower the cost of yeast (if you are using liquid). Once you go all grain you can patch together simple session recipes like SMaSH brews that are inexpensive. You can also buy hops in bulk, which is a huge cost saving. If you are making several similar types of beers, especially not highly-hopped beers, you can use one or two types of hops, bought in bulk, where the recipes may call for ounces of 4-6 different types of hops. I bought a pound of Fuggles a year ago and used it in wheat, porter, saison, tripel, dubbel, belgian golden strong, sour, pale ale, kolsch, and brown ale in different ways over about 30 gallons of beer (and I still have some left). That was about $22 with shipping. If I had bought that much hops from a HBS by the ounce I would have easily spent $32-64 plus tax. You could buy 2-3 types of hops and easily get plenty of variety for low cost.
