To purchase land without having any money down, you will typically need to find a seller that is willing to issue a land contract without any sort of down payment. This is rare, since sellers often want a down payment as a sign of a "good faith" deposit.
Some large companies that sell tracts of land are willing to have these types of deals if you are willing to pay a large amount of interest with each monthly land payment. Remember that you will probably also be responsible for the annual taxes on the property during the time that you are making payments on it, as well as after the land is paid off. Association fees might also be due, and these would be a separate monthly payment.
If you're wondering about the specifics of any type of land deal, contact the company in charge of selling the land. This might be a real estate company that has agents who you can speak with via email or on the phone whenever you have questions about the property. If you don't know the physical address of the company and cannot find it listed anywhere, be careful about doing business with them.