For a good sound and bass thump, a single powered speaker would be perfect. JBL Eon 615 is good. Has separate channels to adjust each input’s volume. Most powered speakers have this ability. I recently upgraded to QSC K12.2s. Higher prices but worth it. I have 4. I take as many as I need depending on the venue size.
For coffee house gigs, I humbly recommend the Yorkville NX10c, a 300w 1x10 coax speaker/monitor that measure an astounding 12X12X13, and sounds great. You can usually find them used for around $400CDN…
I am using an EV Evolve 50 system which is similar to the Bose L1 system. I have tried the Bose and to my ears the EV sounds better and is cheaper. I run vocals, guitar, bass and BeatBuddy through it and I am very pleased with the system. It is great for the BB, lots of thump and clarity. I keep turning around to relate to the drummer…where is he…oh yeah!