I started a 529 plan for my youngest when she was 6 months old. Automatic payments $100 monthly. It currently amuonts to about $7700 last I looked (well maybe about 7000 after the past few weeks). The cumulative earnings today over the past 5 years is about the same as a savings account (almost zero).
But at least it has been pain-free. Never missed the 100 bucks once I started. I expect that gains going forward over the next decade might outpace a savings account.