Adenaria floribunda is a native species found in tropical regions of South America used as a traditional medicine. Ultrasound-assisted extraction (UAE) is an extraction process known to increase the extraction yield, reduce extraction times, and use low temperatures. This study aims to obtain water-based extracts from A. floribunda stems using UAE, hot water extraction (HWE), and Soxhlet extraction and perform an economic analysis. The global extraction yield (GEY) and total phenolic compounds (TPC) of extracts ranged from 5.24% to 10.48% and from 1.9 ± 0.44 mg GAE g−1 DW to 6.38 ± 0.28 mg GAE g−1, respectively. Gallic acid, catechin, and ferulic acid were identified in the extract using HPLC-UV. Results indicate that Soxhlet extraction has the best performance regarding GEY and TPC. However, after performing an economic assessment, the cost of manufacturing (COM) of Soxhlet extraction (US$ 5.8 flask−1) was higher than the UAE (US$ 3.86 flask−1) and HWE (US$ 3.92 flask−1). The sensitivity results showed that obtaining extracts from A. floribunda by UAE and HWE is economically feasible when the selling price is above US$ 4 flask−1. Soxhlet extraction is a feasible technique when the selling price is above US$ 7 flask−1.