Option 2: the shared van
The shared van is the cheapest visa run from Da Nang that actually finishes in one day. At 1,000,000 to 1,200,000 VND per seat it costs four times the bus ticket, and it is still the budget winner once you count the night you do not spend in a guesthouse and the workday you do not lose.
The day runs like this. Pickup happens between 04:00 and 06:00 from your hotel, apartment, or anywhere else across Da Nang, including Hoi An with a short detour. The van heads north over the Hai Van Pass, through Hue, and west toward the border, with comfort stops every couple of hours. At Lao Bao a fixer handles the exit, the walk across to Densavan, and the Laos entry stamp, so you are not figuring out the forms on the spot. Then you reverse the process, get your fresh Vietnam re-entry stamp, and drive back. Door to door, 10 to 12 hours, same calendar day.
Who picks the van: solo travelers, backpackers, digital nomads on a budget, and anyone whose main concern is the lowest realistic total cost. The tradeoff is control. You move with the group, so pickup order and stop timing follow the vehicle plan. If your visa is already inside its last days, or you want to set the pace, the private car is the safer call.
For the math: one person, shared van, comes to 1,000,000 VND plus the Laos border fee and visa costs. That is the cheapest complete same-day run you can book from Da Nang in 2026, and it is the option this page recommends when "cheapest" means "cheapest without sleeping at the border."