Stay away from Monroe. Search the web and you'll find they don't have a great reputation. I had them twice on previous cars and it took about 3-4 weeks before they settled in (rode high and a bit firm). At about 20-25,000 miles they started going soft. It's not a money saving proposition by having to keep changing them. The labor costs alone would be more than the extra expense of buying better struts in the first place. Also, cheap quick-type strut assemblies have garnered complaints about developing clunks due to failing strut mounts (the top part of the assembly that bolts to the body ---open the hood and you'll see 3 nuts on the protruding studs). If you are planning on keeping the car then struts are not an area to go cheap on.
That said, some members here have reported satisfaction with KYB so that seems to be the consensus and those would be my first choice when the time comes.
Maybe some other members will add their thoughts and experiences.
Mazda CX-50: Forging Its Own Path from Shared CX-5 Roots