If you just want an "off the shelf" generic rifle or two for casual shooting then building your own is not cost effective, but can still be intellectually stimulating like any other hobby.
If you are a mature, experienced user your personal requirements may be better defined, and a "custom" build would become more desireable and appropriate, and you will either pay an expert, or learn how to work on your personal weapons. Sure, you might build something, find out it sux, and tear it down for recycling into another configuration. Same with blingbling toys. The money spent, even unwisely, is still a positive down payment on your educational progress.
Try to stop counting beans, and start looking past the few dollars difference involved. QUALITY COSTS. And high performance in any endeavor never comes cheaply. You have to decide for your self if "running with the big dogs" is something you desire, need, or can afford to do.
The first time I shot a 200 yard group with a self-wrenched Arf that beat my previous personal best with a Remington 700VS was all the "reward" I need to justify my efforts and expenses.
Paladin