To keep chickens cheap, stick to production hybrids or leghorns, only get as many as you need, replace them at 18 months mercilessly, feed a balanced feed as much as they want (pellet especially), but you may want to take it away once they've filled up to prevent pests from dining, and free range. Some producers also cull broody birds.
Not really what hobbiests want to hear, but that's how you do it. That's a lot of what I don't do.
Now in regards to that shed, I think you might be able to build better for cheaper. That plastic guy is also going to need a ton of ventilation unless you only intend to get two or three birds. No deep litter in that guy. Find a buddy with scrap wood and tools and build something tight. People also love pallets as building materials. For a reference, my first shed cost was free made of scrap wood in a few hours. My next shed...well, the husband got to that project. It was not cheap. My goat house is a 6x6 shed with a dirt floor and lots of ventilation yet is tight and secure and it was $200 because the husband wanted a real roof on it. It would have been less than $90 otherwise.
I'd also just get a metal feeder from your feed store and build a nipple waterer with a 5 gallon bucket and horizontal nipples. If they're good enough quality and you keep the metal feeder out of the rain and wet they will last for years and years (at least the feeder, I'm still testing my nipple waterer). Hang the feeder in the coop, put the waterer on a cinderblock outside. 2x4 makes an excellent roost. Plastic colored tubs from the hardware store with chicken sized holes make great nest boxes. They can be weighed down with a brick and filled with shavings.
I'd also always remember to lock up the birds at or before dark. Replacing eaten birds is expensive.
That's all I can think of. I'll follow this thread for ideas on what else I'm not doing.
