I Heard an FM complaining that the clothing allowance wasn't enough " for socks and underwear". I laughed and said "If you buy a season ahead (clearance) hit a few mom to mom sales you can outfit a kid completely IN BRAND NAME for around 150 " The trainer was impressed but FM didn't like getting schooled by a youngin.
I'm the same way with my kids, but keep in mind it isn't as easy to do with foster children because you don't know a season ahead that you'll have a 5 year old girl and a 3 year old boy for example. Maybe you'll have a 3 year old girl and a 5 year old boy instead... They show up with the clothes on their backs (hopefully) and immediately need socks, underwear, a few changes of clothes etc. And you won't get their stipend for a month. So you need to have some cash available up front for immediate needs.