Yes. eSIMAdvice currently lists 6 eSIM4Travel Niger plans.
The cheapest eSIM4Travel Niger plan is Niger · 100 MB · 1 day · 4G · Celtel, at $0.98.
Niger · 500 MB · 1 day · 4G · Celtel has the lowest price per GB right now: $4.10/GB ($2.01 in total).
Yes. The prices shown already include the ESIMADVICE coupon where it applies.