And to get this right. I need to purchase a domain name and then hosting as well?
What's the general cost for all this?

I would like to suggest you Hostdone.com web host - believe their cheap web hosting plans will meet your requirements.
They also provide cheap domain registration service - $9.99/Year.
And if you order their shared hosting account, you will have so many useful scripts for successful running of your sites.
The code (hostdone20) will save 20% off the price for you.

I would recommend you not to put all the eggs in one basket - register domains and buy hosting separately.
Eurodns.com is one of the best places where you could register domain names. It offers nice specials and discounts. It is ICAN-accredited company.

Nice and cheap hosting opportunities you could get from Platnethoster.net web host.
Good communication and customer service is key to a great web-host, and it has these qualities in spades.

Can also recommend hosteasier.com.. Their services are appreciated for the high server reliability, the connection speed and the excellent technical support available 24/24 hours via ticket, email or by phone.
Pricing is cheap.