I think it depends.
It would be very easy, if I were not determined to lose weight to say that I just cannot afford healthy food. I have heard it many times. I think it a simple excuse that is true enough if you don't look into it further. We COULD eat top ramen and PB&J for much less than I spend on groceries. It is possible to be a healthy, thrifty shopper but maybe the entire process takes more time and mental energy than some are willing or able to give. Some people also site the cost of smaller clothes as an issue to why they can not lose weight.
The flip side of course is that what I do with my body, and what I put into it is something I can control. I know that it gives me a renewed sense of optimism as I discover the things I CAN do. Every time I run a longer distance for the first time I am surprised to find that I did not, in fact, die from exhaustion.

-Maybe we can't buy a house right now, afford a vacation, or a million other things I could think of that we don't actually NEED but I am happy and on my way to a healthy body and life.