My son unfortunately has brushed the leading drivers side edge against a low wall gouging but otherwise not deforming the front bar.

My question how easy are the to self repair, can I fill, sand , undercaot then take it repair shop for respray or are these a throw away item?

nah not throw away. can fix by giving a roughen up with 80 grit paper,drag a single edged razor blade over it a couple of times to remove any hairy bits,mix up and apply bumper filler.allow to dry,rub back with 80 grit on a block,leaving it slightly high,repeat with 180 and 320 grit. plastic prime then your ready for paint. a crash shop would probably charge around $300 for fixing the damage and paint.

Cheers elf100capri anything to save money