Had more experience than I'd like with lice.

The only solution that ever worked was the diligent use of a LiceMeister comb. A couple of evenings with this and they're pretty much gone for good so long as you wash and vacuum the environment too. There are copycat metal combs on the market. None work as well as LiceMeister.

Our school nurse swears by a dilluted spray of tea tree oil as a preventative. Can't say if it passes scientific muster but her anecdotal experience is good. Tea tree oil has other uses too (treating burns).

Both cheap and low tech.

latvija