Not everyone wants to, or can, pay upwards of $50,000 for the fully custom design of their home. If we had the money to spend on exactly what we wanted, we likely would. But many of us cannot afford that, so we don’t attempt to.
To offer a more affordable alternative, Earthship designers (Earthship Biotecture is not alone in this any longer) make standard plans available for sale that are essentially kits that you tweak in the same way as when buying a “custom home” in a suburban development. Maybe the plans are customized with your name and a few choices in materials or finishes, upgrades like a vestibule and that is it. These plans can cost up to $10,000 themselves.
Here is a list of available custom upgrades available as of this writing, and an explanation of what they are and do: OPEN END This essentially creates an enclosed quarter circle vestibule on one end of the greenhouse. This allows light in and expands the greenhouse capabilities, while helping to keep some of the dirt and dust and snow outside. This option adds functional square footage to the greenhouse for growing, but does not increase habitable space. GARAGE The garage in Earthships is constructed by the same means as the Earthship itself, often even utilizing vigas for the structure. This is an expensive addition due to the large vigas required to span the space, concrete for the floor, and the garage doors. Up to an additional 200 tires may be required. Additional heating may be required, and windows should be provided along the south and/or west walls if a greenhouse is not. AIRLOCK / VAULTED ENTRY In the old days, this was called a vestibule. Vestibules are used in climates where to want to offer a "buffer" between the inside and outside. Vestibules are a great design element for use on the west side of buildings in Taos. The reason being that the prominent wind direction in the summer is from the west, and that wind carries heated dust from Arizona across the desert and straight into your house. A vestibule traps some of that dust and cools the air before it gets inside. A vestibule is also a great idea when used as a mudroom in the primary entrance of the house. As designed, the vestibules available at this time are too small for that use. Make them a bit deeper, add shelves and hooks for storing tools and boots and coats, add a bench for taking off your snow or work boots, and enjoy the many benefits of this space. 
The vaulted entry adds a sheltered vault to this vestibule. It is pretty and prevents some snow and ice buildup right at the door. It can have a detrimental effect on the amount of light coming into this end of the structure, so plan for an exterior outdoor light in the vault. DUPLEX An Earthship plan is mirrored down the middle to make one Earthship into two separate functional spaces. SPLIT LEVEL Split level Earthships work better when building on a sloping site, as long as you are and remain fully able. However, there are good reasons that split level houses were abandoned years ago – they make maintenance and regular cleaning harder; they require additional structure that is harder to build and more likely to require a structural engineer’s or architect’s stamp to get past permitting; they make carrying your baby and groceries and laundry and vacuum cleaner around the house more difficult; and they lead to injuries from people falling down stairs and steps. They are also not accessible unless you are perfectly abled and remain so – no twisted ankles, surgeries, broken bones, blindness, or wheelchairs allowed.
The “custom plan” option, being largely un-customizable, has left some people we talked to wondering what they were really getting for the many thousands of dollars they are paying for these plans, especially when those plans are not guaranteed to get permitted. The permitting issue is something that takes me aback a little, from working in the design profession for nearly 20 years now. If I designed a home for someone that they could not build, I would be taken to court and have the pants sued off me. The common response to this concern is, “The Earthship is an experiment.” But if I put myself in the shoes of a potential buyer, I cannot help but to think “…but my life savings is not an experiment for someone else to make for their cause, with my money.” 
One of the issues that people have mentioned to us regarding Earthship plans is that if you already have a plan set - if you bought a copy from a previous builder or bought stock plans - to get those plans modified is going to cost quite a bit. One of our sources shared that they were quoted an upfront cost of $150 per half hour for a phone consultation. If that is indeed true, that is an astronomical price. To assume that anyone can provide great service at that price point over the phone is to presume a lot. Further, that meeting does not promise any results. All you are buying is time. In architecture firms with some of the top architects in the country, for actual face-time with the lead architect, one might pay $200 per hour. Most architects and designers will come into a meeting with both of you knowing what the expected deliverables will be after that meeting. Progress will be made. That is why you meet. A phone consult with no end result does not sound like a good investment.
A good designer will help you to get you a home that you will love. That is part of the reason why we believe a buyer is better off to contact a regional architect rather than an Earthship designer to get your plans, especially if you want to use alternate materials. An architect or established residential designer will get you to plans that will work. That is their job. It can cost more but it works the first time. The expert gets to share their recognized wealth of knowledge to persuade the permitting authority that the system they are building with works. It takes all of the pressure off the client. That is how design is supposed to work. Plus, humans have been building earth-sheltered structures for 10,000 years. It is not like an Earthship designer has the market cornered on how to do great earth-sheltering. 
We will attempt in later chapters to help you answer many of the questions a designer would and should answer, so that you can get the best design possible with or without professional help. The key is to know exactly what the designer needs to figure out in order to maximize the value of the time spent on your project. It is easy to dramatically cut a design budget just by minimizing the amount of preparation and research the designer has to do.