To get an idea of price, you need to have an idea of what you want. If you are trying to save money and not break the bank you need to pick items that are the best bang for the buck, instead of looking at "the best components"
You need to choose where you wish to be in a processor first. Celeron's are the entry level, then Pentium, i3, I5 and i7. The Pentium is really a good performer, but the i3 gives you hyperthreading and is a good midrange processor. the i5 is the step to Quad Core and is a great performer and gives more longevity and is still quite a bit less than the i7.
Sure the Z97 chipsets are the better or higher end chipset, but the B85 chipset, like the ASUS B85M-G is a good mid-range chipset that supports up to 32GB for about 50.00 less and is a good performing board.
a decent 500 watt power supply is fine. you don't have to bread the bank with a 750 or larger. a ThrermalTake Versa case has good ventilation at a reasonable price, You don't need a GTX 750 or even a 650 for video editing necessarily, these cards were geared to high frame rates for gaming. the onboard video is pretty good these days to. Depending on how graphic intense your video editing is, you may be able to use a good 2GB GT630 video card for your needs and cut a couple hundred dollars off that gaming card.
How much memory? more is better, but you only get benefit of more memory if you are working your computer. 4 or 8 Gb is enough for most people, Memory is not expensive, and with 4 slots, you can add as you go if it is not. you get better (but not blazing difference with dual channel) but you wouldn't probably see a difference with one piece of 8GB running in single channel mode. add a second and you get dual channel when you are ready for 16Gb and you still have two slots open if you need to eventually get to 32GB.
Solid State hard drives are blazing in speed, but still expensive, especially for the better performing ones. all SSD's are not created equal. around a 256GB is a good size, but for a nice one you can expect to pay over 200 just for the drive where a good standard SATA drive will cost you under a 100.00 if I need more storage then I can afford in an SSD, then Seagate's 1 and 2 TB drives with 64MB Cache are good performers at a bargain price.
Do you need an operating system or are you going to use what you own? that can make 100.00 difference or more depending on edition. We still sell both Windows 7 or 8. no price difference, just an option.
Most systems come with a DVD-RW, Blu-Ray adds to the price. most software is downloadable these days and DVD drives are being used less and less. Blu-Ray has not moved into the mainstream yet, and many are claiming DVD's will disappear eventually just because of the high bandwidth speeds of the internet and so much available on-line. Do you need Blu-Ray for your video editing?
Narrow some of these options and I can get you a pretty close estimate of what it will cost you to build one. Don't expect to save a ton on building your own, but you won't get one of the big computer companies cut corners on your computer. You will be able to save some money though. Don't fall for the nice i5 prebuilt that is cheap, because the i5 was the only decent quality part in the computer.
deciding some of these will narrow where you will fall in price. Choosing some of your preferences and you can get a closer estimate in price. you can spend 400.00 to 800.00 and still build a good performing, reliable computer. you either need to decide what your budge is, and then configure what you can buy to get the best for your money, or decide what you need in hardware and see how much money you need to get what you want.