Don't worry too much about it being on the wrong forum. It's close enough.
As for advice, well.. Yeah, basically, don't pay more than about $15/year (american) for a domain alone. With a "raw" domain, you have to have DNS servers to host it, and then those DNS servers need to point at a webserver and email server that will handle web (and email) traffic for it. Most "packages" often come with at least DNS service, but they up the price on you too. If you're planning to use it for a site here on xepher.net, I provide all the services for free though, so you JUST need the raw domain.
As for where to go... personally, I use godaddy. Why? Because they're big enough that they have to know what they're doing, and they can't just disappear/scam you. I'm not saying their service is great... it's actually kind of potluck. A couple of times I dealt with them and got amazingly good service for a complex issue. Other times, it was typical brain-dead customer service fail. For a raw domain though, you should basically NEVER need service... You have to login once a year to renew and confirm your contact details and that's it. The downside to godaddy is navigating/avoiding their pushy sales stuff. I actually spend more time deleting their "renewal reminder" emails (they start sending them like three months in advance, and when you have a lot of domains...) than I do actually interacting with their site each year. And if you don't know what you're doing during checkout, they try like a hundred times to sell you on those extra services like "whois privacy" and crap like that. It's basically like dealing with wal-mart. It's kind of a crummy place to shop, but you generally know you'll get a good price and that they aren't stealing your credit card info. That said, EasyDNS has had a pretty decent reputation too, though they focus on providing the actual DNS services, and I don't know if they even offer a bare domain registration.