I was supposed to be a latchkey kid growing up, but 1. the term wasn't used widely in the '60s, 2. we never locked our doors, so I didn't have a key, and 3. I rarely went home before suppertime.
My advice: spend as much as you can on linens and skimp on dishes. It's a happy feeling to be tired and fall into a bed with 800-thread-count all-cotton sheets.
Interesting how we write our own back story for this sort of thing. Mine has her frustrated because she had been prompting them to say Thank-You for a while and they still did not do it on their own.