When you say that you are getting the patio prepped, what does that mean? Will it be attached or touching the house? Will you drill holes into your existing slab and epoxy rebar into those holes to tie the patio to the house? Are you using rebar or wire mesh? Wire is cheaper, but it's pure junk and impossible to keep in the middle of the concrete. Anybody who says they pull it up while spreading the concrete is misleading you because they just walk right over it again and push it back down. For a pad, I would only use rebar, and it would be set on chairs. I do not trust anything else, and I wouldn't rely on anything cheaper of faster. Rebar is proven and it works every time.
At $5 a square foot, that's a good price if it includes the concrete.
Be sure to get multiple bids if you don't already know the guy you are hiring. In every case that I've been hired to fix what others did, they guy they hired was the only one they talked to.
Eddie