shop around
Setting up a cart in a nutshell.
Location, get a good lay as to how much space you have to work with and if it's going to be indoors or out or both. Choose your equipment and cart by shopping around, look at your options in this area, also make sure you are getting something that's not going to overdo/underdo your operation.
You are needing more then just a box on wheeles, there is equipment and supplies that add up, so $12k is a good figure to set aside to have everything you need to open shop, more or less depending upon how far you want to invest in supplies and how high end you want to go with the equipment and facility.
You need to be up to code which can be an obstical in 3 areas. 1st, you need access to a full commissary, ie. 3 compartment sink, mop sink as well as will normally be drawing minimum of 40 amps of power to run everything so may require an additional high voltage outlet. And you'll need to store it, or keep it secure at night. Other then that, it's a nice small package operation that has serious potential to generate a formidable income or more.