If you want to build a mobile tiny home, a lot of people get a little ways into the project and decide to
sell. Look on Craiglist for tiny house "shells," which is basically just the framing and exterior walls without siding. Don't just look near you, but be willing to drive one weekend and haul the house back from a more distant location. If you can find a good deal on a shell, it can save you time and money. Be very cautious, however, and, if possible, see if you can entice a contractor friend or someone else with building
experience to go with you and evaluate the purchase before handing over any money. As for trailer, car haulers are a good option. For foundation built tiny homes, research things like how to construct a rubble trench foundation, how high to make the foundation based on your climate, and techniques for doing things to prep for the build yourself. A professionally installed pad or foundation can be very expensive, and or a good reason. It is vital. But there are tried and tested methods of doing it yourself if you have the patience to learn.
Divide the project into sections and decide what you are going to want professional help with and what you want to do yourself. I recommend getting help with framing, roofing, plumbing, gas utilities, electrical, and insulation, or spending
enough time to get a really firm grasp on the topic yourselves. These are things you do not want to mess up. Other than that, you can find guides and videos
online to do just about anything. Diving it into tangible, separate projects is key to not getting overwhelmed. Always do windows before siding. Don't be afraid of exposed plumbing, as this will be much easier to fix if needed anyway, and it removes a lot of boring holes in your framing. A lot of people will be curious and interested to be part of your project, since tiny homes are fun an unique. Take advantage of this to find both professional and amateur help. Consider designing and building your own furniture, as finding stuff small enough and precise enough to meet your needs may be difficult. Be aware of
local laws and codes, and act according to your tolerance for risk.
If you do not have access to a wide variety of tools, you need to remedy that if you're going to do conventional construction of your tiny home. A drill is necessary. A table saw is wonderful and will make your life a ton easier, but a circular saw and some sawhorses will work. A jig-saw is probably necessary. A nail-gun will make your life easier, but you can stick to a hammer and nails.
Know that you will probably go to Lowes, Home Depot, or another building supplier every weekend for a year while building your tiny house. You will be buying and returning things all the time.