these are the limits i have in the list of my exchanges that i use (numbers are satoshi):
bitfinex: 1,000,000 (0.01BTC)
bittrex: 50,000
c-cex: 10,000
NovaExchange: 10,000
BleuTrade: 1,000
Cryptopia: 500

also i believe btc-e is also 10,000 and the 0.01BTC limit is only for their metaTrader not their Api regarding their main platform.

p.s i have never seen anything lower than 500 satoshi and there is no point for it either.