I think newegg.com has them, as well as tigerdirect.com
You may also want to check pricewatch.com , and ebay as well if you're a member.
If all else fails just use google, i'll try and find a good combo for that amount of money... I'm busy right now tho
The only thing is, that while you get a combo.... you still don't have an agp video card. But you can really save up 70 bucks or so and get a good one for HL games... Or even 50 dollars if you are on a tighter budget.
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Scratch the mobo combo idea... While it's what
i would do.... I'm not so certain it's the best move for the more beginner`esque individuals.
Another alternative, which i think would fit you very well. Would be to buy a barebones kit. Barebones kits can be found on tigerdirect (newegg as well, but they are much more expensive). They consist of the basic essentials for a novice builder looking to upgrade & customize in the future.
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1417186&sku=P459-2000 C
That's a good cheap set-up for your pricetag. I
believe the video is onboard graphics, which is nothing to brag about. But this will give you a much better computer than you're probably currently running considering you're on a mobo that has no agp slot. Likely you're on an Pentium 400mhz processor, this set-up contains a 1.8ghz processor. That's a 400%+ increase in speed (assuming you have a 400mhz).
It also has DDR ram, which you're more than likely (well... surely) running SDRAM. DDR ram is twice as fast as SDRAM. So not only are you getting double the ram (set-up comes with 256mb DDR) but you are also getting twice the speed. Also a huge increase. (again, assuming you have 128SDRAM)
The only real faulter is the onboard sound & graphics card. But it will make do as a good replacement computer if you're looking on upgrading for the future at the cheapest price you can get. Once you save up 70 bucks or so after you have purchased this set-up.... I'd post again and start asking about cheap video cards that are worth the performance.
I think that's the best solution to your problem...<3
*edit*
If you're willing to save up a little more (doubtful
) ,then I would take this set-up
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1359517&sku=A458-2010 E You wont have to buy a new video card, and it's not as much trouble. But it is $300 dollars...
But the other set-up i think is a great solution. And you can get practically just as good a computer for nearly half the price... (not including the video card you are going to want to buy)