There was an exception to the general land distribution of the Israelites: the tribe of Levi was not given any land. Instead, they were given 48 “walled towns,” or about four per tribal area. These towns served an essential function in this agricultural/pastoral economy. The towns contained the skilled workers that supported the farming and herding surrounding them. So here were found the carpenters, metal smiths, harness makers, wheelwrights, etc. that were needed to make the economy more efficient. Here were found the experts in such public works as roads, bridges, and irrigation systems. Here also were found writers, traders, and perhaps weavers of cloth beyond the abilities of the people of the land. The Levites filled these jobs.
Furthermore a Levite man only worked in his religious capacity, which was to preside or assist at the site of the Ark of the Covenant, once every twenty-four weeks. For the other twenty-three weeks, he was back in his hometown, one of those forty-eight “walled towns.” So for over ninety percent of the time, he was pursuing his profession or selling his skills, back home. This goes against the conventional wisdom, which seems to put forward the notions that (1) all the Levites were priests, and (2) their full time job was at the site of the Ark, performing priestly duties.
So the Levites had the urban jobs in the economy of ancient Israel. They had an income. Some of them did well, while a few did not. It’s important to keep this in mind, especially when one discusses the Tithe.