The server is easy. Hetzner,de are fairly cheap and have predictable costs. See http://www.hetzner.de/hosting/produkte_rootserver/ex40. If you don't need something so powerful there are many cheaper cloud services.

You can buy domains from eurodns.com or gandi.net, I think both of them will let you use their DNS servers so you don't need your own.

Servers and domain names are easy. What's your business plan?