The lowest price I currently see for an D26 on Ebay is $63.50, that's shipped from HK and no battery or charger or useful guarantee since you'll have to put return shipping and wait out a 6 week turnaround.
Meanwhile, my Volador 1000 is $50 from Amazon Prime with a battery and charger. It's also a bit more compact both in length and circumference. I can get it in 2 days and they handle warranty work in the US. Or you can pay a bit more and get it from someone like Manta or DGX who you know will be there for you if there's a problem.
As to the battery, you have to consider your use case. Because I only use a light occasionally during daylight dives and I rarely use the high setting on night dives, I easily got 5 dives between nightly recharges on the 18650 on my last liveaboard trip. So the extra capacity of the 26650 isn't worth the trade-off for me.
Meanwhile, my Volador 1000 is $50 from Amazon Prime with a battery and charger. It's also a bit more compact both in length and circumference. I can get it in 2 days and they handle warranty work in the US. Or you can pay a bit more and get it from someone like Manta or DGX who you know will be there for you if there's a problem.
As to the battery, you have to consider your use case. Because I only use a light occasionally during daylight dives and I rarely use the high setting on night dives, I easily got 5 dives between nightly recharges on the 18650 on my last liveaboard trip. So the extra capacity of the 26650 isn't worth the trade-off for me.