In the EU zone Bitstamp.net has zero fee under €1000/month. Minimum buy €10. Your can open limit orders below the market price and try to save some %. It has an API so you can easily script a DCA routine. But it is full KYC

Pocketapp.com has 1.5% few, "light" KYC under €900/month and it is easy as send an (instant too) SEPA to automatically buy at market price with direct transfer on your own wallet.

Fees are related to convenience, security and privacy, make your choose :)