> 2,500x magnification
You can, of course, magnify as much as you want; but you won't see more detail.
"Junior" microscopes often brag of a 1000x magnification; but that only works if the lenses are really good, and in that kind of microscope, they aren't.
You need 1000x to see bacteria. Bacteria are really boring to look at; they appear as undifferentiated spheres or rods. And even then you can't see them at all without fixing and staining.
Single-lens microscopes suffer from spherical abberation (only the centre of the image is in focus) and chromatic abberation (everything has rainbow fringes around it). These problems are worse with greater magnification.
As far as I can tell, the best "mass-market" compound lenses these days are made in China.
Source: I bought my son a microscope a few months ago; he said he wanted to see bacteria. I hoped a "junior" 'scope would get me off the hook, but I consulted suppliers, and they warned me off, and told me quite a lot about how to choose a 'scope. I also bought him a set of stains and solvents, including a gram-staining kit. I did a fair bit of research before I spent money.