With the right software, you could theoretically use a personal computer as a web server, but the issue would probably come up with the ISP who has to act as a middle-man for your constant internet requests. You can always check with whoever provides your home internet, but its pretty rare that they would let you run a webserver on a normal internet account.
Otherwise, the scope of your goals sounds pretty reasonable for a novice and a perfect fit for a shared hosting environment. Typical price ranges would be like $6-8 a month after
coupons, and maybe $10 a year for domain registrations after the first free one.
If you're looking for a cheap way to get started, the Dreamhost coupon 75for1year will take $75 off the normal $120 annual price for hosting + 1 domain, so you pay less than $50 US for the year of hosting and domain name, $10/yr for extra domains etc... (If you want more domains or a different
Dreamhost coupon, check out the others including discounts for monthly accounts)
From there you can install different CMS platforms with automated scripts. In a few clicks you can have an easy way to edit your online content and if you want to get more involved from there you are free to mess with the code as much as you want (at your own risk!)