IMO, ANY medium of choice can get expensive, or relatively cheap . Hydro, soil, soil-less. Generally, and especially over time, the more you put into it, the more you are rewarded. In a business sense, it takes money to make money. ( not implying your growing for coin).
With growing, you have to make one big leap of faith. You have to ask yourself if I plan on growing seriously, or just as a hobbyist. Obviously the hobbyist grower is going to have less $ invested, but he/she gets by and it satisfies their desires. IMO, a serious grower put the time and effort to understand his craft, and is willing to commit the necessary $ to get the productivity he/she wants. The idea is to understand your craft before you attempt it, or attempt it on a larger more costly scale. Obviously nobody just wakes up one days and starts a 40k hydro farm. They work there way there. So, with that, start small and progress. It will save your $ and heartache.
IMO, In life, you work with what you got. If you got the knowledge and coin to run a hydro op, and it satisfies your desire/goals then you will spend what you can/want.
Last week I was speaking to a young gent who was about 24-26 years old and he wanted to know "about how much money" it takes to become an artist and start making money. There is no exact dollar amount, ever. Some spend more, some less. Some get great results, some get okay results. Its a journey, and nobody has a price tag on it.
The great thing about horticulture is you can grow within your means. Most people are not going to sell house and home to start their grow op. They simply do what they can , and improve when life permits it.
Im sorry to hear of your troubles. Growing is tuff on a budget, but not impossible by any means. Its extremely rewarding, especially when your doing so under tuff economic times.
Hope this helps
All the Best~