This really depends on:
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your budget (what is “affordable” to one person may be “expensive” to someone else)
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what equipment you want to carry around / how much processing of the photos you want to do
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what you want to photograph (how small, how far away, what else you will be using the camera for besides small insects)
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whether you want to take “nicer”/more professional photos or just ones that capture details needed for ID.
For some uses/needs, a clip-on macro lens for your phone or a hand lens may be sufficient. For others, you may want a proper camera and a macro lens and other equipment to go along with it (flash, tripod, software or in-camera function for focus stacking, etc.). And there are all sorts of gradations in between (newer phone camera, point and shoot camera, bridge camera…)
Some previous threads on photo equipment:
https://forum.inaturalist.org/t/good-camera-for-detailed-close-ups/41474
https://forum.inaturalist.org/t/macro-and-telephoto-lenses-for-smartphone-cameras/9112
https://forum.inaturalist.org/t/hand-lenses-loupes-for-macro-photography/40225
https://forum.inaturalist.org/t/good-cameras-for-nature-shots/1064
https://forum.inaturalist.org/t/what-do-yall-use-to-take-pictures-for-observations/41372
https://forum.inaturalist.org/t/what-camera-do-you-use-for-nature-photography/28220
https://forum.inaturalist.org/t/your-nature-camera/31631