someone is unwilling or unable to make the fairly significant additional investment in a hobby quality battery
Non-rechargeable batteries are so ... 1952 AD, not 2012 AD.
Expensive RC store batteries might be better, but I've been using 2200-2500 mAh
NiMH AA cells bought from Walmart and Target for years on my small robots, with
up to 16 standard servos, and they work fine. I also use 6V SLA batteries on
my heavier robots.
Many people only use Lipo, but that's more preference than actual necessity.
So, you might point out what works good in practice, what sorts of energy levels
they each produce, and what is miserable [eg, Arduino 5V buss, PP9], rather than
trying to sell the case for only what is "best". Engineering is about making good
compromises.