Hello; Building a PC is fun and exciting, and a great way to learn more about the machine too! You can research what motherboards work best with what components, or you can just slap anything together.... the difference will be a machine that works with synergy; (the sum of the parts, working efficiently together, to make a whole). It can be simple, or as complicated as you want it to be!
It's true that building a PC is cheaper than buying one, but it's time consuming, and if you're willing to take the time and read, and learn, then I believe you can build a $2600 system for about $1200... and today, the monitors are cheaper than they were in the past, and that was our biggest expense! Here's some websites to check out; www.tomshardware.com
(for technical issues). For lowest prices, go to www.pricewatch.com; they list items you're looking for, in lowest price first order (including shipping), and they're generally rated, so you know if you'd feel better paying say, one dollar more, for a store that's got a better reputation, or rating... In using pricewatch, there was one store that consistantly came out, in almost all my searches; www.newegg.com, with www.directron.com & www.digi4me.com two close seconds. I think you'll enjoy yourself here! To start, you might want to get a bare bones system, and add to it, as you can afford... stay away from integrated video, (onboard), and "shared ram" systems! I'll also leave you with this piece of advice: a kick *** video card, and ample ram; is far better than spending top dollar on the fastest CPU! Get yourself a reasonably priced motherboard, with plenty of PCI slots, and can handle a good amount of ram for future use... a good video card, with it's own VRAM, and maybe the second, or third fastest cpu... if the motherboard can handle the top of the line cpu, there's room for upgrade, when the top cpu is no longer top!
I have a friend who's got way more time than me, but he builds a system about once every six months, sells his old one (old is six months old, for him!), and he stays current, and the cost is cheap, because he's building a nice system that still brings good money, six monthsdown the road! If you've got the time, it's a great way to keep your pc almost the newest & best there is, without spending a lot! Of course, it takes some kicking around money, because there's some time between your building the new one, to selling the older one.
Best of luck, and Enjoy!;
Marcos