This has been good to me. The LED lights are very helpful, batteries last forever and it is much easier to read hallmarks and the like on watches, jewelry, etc. No more marching around for decent lighting.

Around $5.00
I also use the Peak Scale loupe 7X, mainly for cards. It has a .1mm scale embedded that is quite handy in measuring centering. I have to have a good light source, either good ambient or a flashlight 'in the field'. Around $60.00