Bill of Sale ; Library File Link. Learn more about a trailer bill of sale in Arizona and why you may need it when registering your trailer.Download in PDF or Word here. A trailer may be eligible for a regular registration (one, two or five year) or a permanent registration. The Trailer is to be sold free and clear of any liens, encumbrances, or mortgages. The motor vehicle seller must insert the sales price, nonresident state and Arizona county tax rates and complete all mathematical calculations. All forms are fillable. You can fill it out in Reader and print it from there.