My experience with cheap pulleys sourced from China is that the holes are either too large or off center resulting in unwanted motion of the printer mechanism. Idlers that have built-in bearings typically have very small, low quality bearings that won't last, and are likely to have the same off-center hole to mount the bearings. Filastruder sells Gates pulleys that are properly drilled for about $5 each.
If I wanted a toothed idler I would probably buy a Gates pulley, insert a shaft, and mount it in an assembly that uses larger ball bearings. Otherwise, if you don't need toothed idlers, stacked F608 bearings make great pulleys for 10mm belt. They are cheap and will probably last forever in a 3D printer. I've been using them in my printer for 6 or 7 years and they show no signs of problems.