The 3” tabletop Dobsonians are all 76mm f/4 units with spherical mirrors, which are unsurprisingly incapable of rendering sharp images. Their wide field of view makes aiming easy, provided the eyepieces provided are also up to snuff, but don’t expect high-resolution views. However, if it’s all you can afford, the tabletop Dobsonians still beat having nothing. Performance is roughly equal to a good pair of astronomy binoculars
, which we would probably recommend instead if you are on a very tight budget.