'Normal' depends on what settings you use to create the jpg file.. For example, did you set an output height and width or use the original RAW dimensions straight from the camera. And what jpg compression did you use? And how many dpi/ppi? All those will affect final file size.
As to what's the best format to give to customers, it surely depends on what you expect them to do with the file. As one example, when I license an image for website use its saved at 72dpi and - usually 800x600 pixels (roughly). So that file size will be small, but will work perfectly for the customer's website. So I guess what I'm saying is there's no 'one size fits all' answer.