Yes. eSIMAdvice currently lists 55 Billion Connect Laos plans.
The cheapest Billion Connect Laos plan is Laos · 500 MB · 1 day · 4G, at $1.29.
Laos · 90 GB · 30 days · 4G · 3 GB/day has the lowest price per GB right now: $0.98/GB ($88.14 in total).
Yes. The prices shown already include the ESIMADVICE coupon where it applies.