Unfortunatly there doesn't seem to be any reasonably priced modern kits around.
For my beginners electronics group i most times have to design all the material myself.
Unfortunatly todays kits either seem to have outdated experiments which don't interest most of todays kids like the radio or telefon stuff, or they are expensive and quite limited like those usb/laser/solar-boxes or their authors haven't heard anything about didactics.
In my case language is an additional problem because my pupils usually are in their first or second year of english....so for them there is no available big pool of information on the internet.
Well maybe i will design an electronics kit for schools to adress those issues, if i have a little bit more time.