How to buy bigger amounts of bitcoin/etherium?

I signed up to coinbase and they're limiting me to $250/week. Although in the process to get it raised… not sure how long it will take.

– I'm looking to buy higher amounts, are there any other safe providers to do this?
– Once you buy from that other site is it wise to keep it in coinbase (becuase they are theoretically safer from hacking)
– Does anyone know how big coinbase's limit gets? and how long it takes to get there?