Depends what kind of goals you have really and how you plan to achieve them, but it can be expensive.
Food is generally a wash, I find. Healthy food is more expensive (especially since protein sources are so much more expensive than carbohydrate sources), but if you simultaneously cut out restaurant food and probably most of your booze then it evens out a lot of that.
Gym memberships are important, but not a significant burden I find. My gym is $15 a month and gets me everything I need.
Supplements are where the money pit is going to be. Creatine, vitamins, proteins, thermogenics, pumpers, strippers, stimulants... all kinda pricey if you want to participate. Even more expensive if you want to dip into prohormones or steroids.
The financial commitment, I find, isn't so burdensome that it becomes not worth it (even for someone like me who does not have a huge disposable income at this point in my life). The main cost of the lifestyle is in time and concentration. Not only are you spending time at the gym, you're spending time reading, researching, prepping meals, planning lifting routines, scheduling workouts around your life, calculating nutrients, buying supplies and supplements and special groceries... Yeah. The main cost is time and concentration