Cheap cameras or smartphones for taking pics of small insects at night in near darkness

Daylight examples :

iPhone 6 + hand lens :
iPhone 7 + Ztylus Revolver :

Low-light examples :

iPhone 7 + Ztylus, indoors with no flash:
iPhone 7 + Ztylus, indoors with inbuilt flash:

But it depends a lot on the phone. Newer iPhones overcome low light issues considerably but second-hand may still cost more than Ixus, so perhaps LED lighting solutions as @albertkang said better.

This is iPhone 7 + Ztylus, indoors, same subject as last but holding an LED torch on the subject:

The subject on the last link has a body about 5mm long, and you have to get within a few cm to shoot it. The LED light used is an LEDlenser MT18 torch.