The truth is, we actually cannot mention one state, as the cost of surrogacy varies on a case-by-case basis. Different circumstances can affect the overall expenses incurred during a surrogacy process. Anyways, California is definitely not the cheapest state, as it is the most popular one and surrogates there are in high demand, which means that the average monetary sum they are compensated is above the average in all other states.
If you are considering surrogacy in a different state, our advice is that you ask for estimates in different agencies and get as much information as possible until you find an option that fits your budget plan.