Your best option is to use the wealth quintile (WEALTHQ) or wealth index score (WEALTHS) value that ranks households into groups according to their ownership of various items indicative of relative wealth (relative to other households in the same country at the same time). The description tab for WEALTHQ has links to extensive documentation on how the wealth index is calculated.
WEALTHQ divides households into quintiles by wealth; WEALTHS provides the material to use some other division, such as terciles or deciles, but most researchers just use WEALTHQ.
Many people in low income countries secure most of what they consume via their own agricultural labor, rather than via wage or salary income. Even many who work for others may be paid in-kind rather than in currency. Therefore, The DHS Program did not collect much information on personal or household income, since such information would be biased by excluding or underrepresenting consumption for much of the population.
WEALTHQ and WEALTHS are available for all units of analysis, under “household characteristics–wealth index.” The variable may be missing for a few samples from the 1980s, since this variable was not calculated for some of the earliest DHS surveys.